Reference · household, workshop, electronics bench

Chemicals

Almost all cleaning, descaling, rust treatment and stain removal in a home comes down to six things: an acid, a base, an oxidant, a reductant, a solvent and a surfactant. Have one of each and know where on the pH scale you are standing, and you can manage most of it without buying a special product per problem. This document lists what is worth keeping at home, what each thing actually does, what it ruins — and what you can mix from them.

Know what the problem is but not what to use? Go to the register — arranged by stain and symptom instead of by chemistry.

Version 1.0 Substances 36 Recipes 33 SEEN Units per cent by weight, g/l

Written for Sweden

The chemistry in this volume is not local. An acid dissolves limescale, an alkali saponifies fat and enzymes cut protein apart wherever you happen to live, and the recipes are built from raw materials sold everywhere.

Three things are local, and are left as they stand rather than guessed at: prices are Swedish retail in SEK, the brand names given as examples are what sits on a Swedish shelf, and the regulation described is Swedish and EU law — the permit thresholds, the agencies, the drain-opener rule. Where the shops are named they are named by trade, not by chain. Check availability and the rules where you live.

The emergency number in the footer is the Swedish poisons centre. Use your own national centre.

Where on the scale each thing works

Tap a point to jump there  ·  values are for the ready-to-use solution

Twelve of the substances are missing from the diagram: the seven solvents, plus the surfactant, the thickeners, the glycerol and the carbon. They have no meaningful pH because they do not work by proton transfer — they dissolve dirt by resembling it chemically, or by simply holding on to whatever is doing the work. That is the other half of the toolbox.

01

First principles

Seven ideas that let you guess the right agent for a problem you have never seen before, instead of buying a bottle per problem.

1 · Four dials, not one

Cleaning is the product of four factors: chemistry, temperature, time and mechanics. Turn one down and you have to turn another up. That is why a weak solution allowed to work for an hour at 60 °C often beats a corrosive one that dries in two minutes at room temperature — and why a gel almost always beats a spray on a vertical surface. Before you buy something stronger: check whether you only need more time or a higher temperature.

2 · pH decides which kind of dirt comes away

Dirt divides into two rough heaps, and they sit at opposite ends of the scale.

  • Acid dissolves the mineral. Limescale, rust, urine scale, milkstone, concrete slurry, tarnish on metal. The acid protonates and dissolves the salt or the oxide into something water-soluble.
  • Alkali dissolves the organic. Fat, oil, protein, soot, skin oil, food residue. The base saponifies the fat — breaks the ester bonds — and makes it water-soluble.
  • Neutral (pH 6–8) cleans most gently. Painted surfaces, natural stone, aluminium, treated wood. Here the surfactant has to do the whole job.

The practical consequence: if an agent will not bite, change end of the scale before you change strength. Limescale in an oven will not yield to more caustic soda, however much you pour on.

3 · Like dissolves like

Solvents do not work by pH but by polarity. Water is strongly polar and dissolves salts and sugar. Heptane is entirely non-polar and dissolves wax, tar, oil and rubber cement. Isopropanol and acetone sit in the middle and can do a little of both — which is why they are so useful. When a stain will not come away with soap: ask whether it is greasy or mineral, and choose a solvent of matching polarity.

polar ← water · glycol · ethanol · IPA · acetone · ethyl acetate · white spirit · petroleum spirit → non-polar

4 · Chelators make everything else stronger

Calcium, magnesium and iron ions in tap water ruin surfactants (they form lime soap), break down hydrogen peroxide, and bind the dirt to the surface. A chelator — citrate, EDTA, GLDA — grips the ion in a pair of tongs and takes it out of play. A couple of tenths of a per cent of chelator in a mixture can do more good than doubling the surfactant. This is the single commonest shortcoming in home-made cleaning agents.

How much you need depends on the water where you live. Swedish tap water ranges from under 3 °dH in parts of Norrland to over 15 °dH in the limestone country of Öland, Gotland and the south-west. Your municipal water works publishes the figure. Below about 6 °dH you can skip the chelator in most recipes; above 10 °dH it is the difference between an agent that works and one that leaves a grey film.

5 · Ten degrees doubles the speed

The rule of thumb for reaction rate: roughly a doubling per 10 °C. Sodium percarbonate is nearly useless in cold water and effective at 60 °C. Descaling at 60 °C takes a quarter of the time it does at room temperature. The other side of it: peroxide decomposes four times faster as well, so a warm peroxide solution has to be used at once.

6 · In a porous material you draw out, you do not wash off

Concrete, brick, natural stone, unglazed tile, untreated wood and mortar have a pore system that the stain sinks into. Everything that works on the surface fails there: you take away the film, and a few days later the stain has migrated back up. It is the same thing that makes an oil stain in the garage seem impossible, and shoes smell again as soon as they get wet.

The method is called a poultice and it reverses the direction. Mix the solvent that dissolves the stain with an absorbent powder into a paste, spread it on thickly, cover it so that it does not dry too fast, and then let it dry completely. As the solvent evaporates it travels upwards through the pores and carries what it has dissolved out into the powder, which you then sweep away. Slow evaporation is the whole point — which is why white spirit is better than petroleum spirit here, the opposite of what holds on a non-porous surface.

The same principle works with any solvent at all: white spirit against oil and wax, dilute acid against rust in concrete, water with surfactant against anything water-soluble. It is the carrier you change, not the technique. See recipe 28.

7 · Rinse, and then rinse again

Almost all damage to materials happens after the agent has done its job, because residues were left behind. Acid drying onto aluminium, caustic soda left sitting in a crack, oxalic acid left in wood that is then lacquered. Rinse copiously, and neutralise when you have used something strong: acid residues are taken up with dilute soda ash — 20 g of anhydrous soda ash per litre of water — and alkali residues with citric acid at the same strength.

02

Acids

Against everything mineral: limescale, rust, urine scale, milkstone, tarnish, concrete slurry. Sorted from mildest to most aggressive.

Citric acid Anhydrous or monohydrate · E330

C6H8O7 CAS 77-92-9 · monohydrate 5949-29-1
pH 10 %≈ 1.8
pKa3.1 / 4.8 / 6.4
Solubility59 g/100 ml
FormWhite powder
Price60–100 SEK/kg
Sold byBrewing supplier

Why it is first on the list

Citric acid does two things at once: it is an acid and a chelator. It dissolves the limescale with its protons and then binds the freed calcium in a complex so that it does not precipitate again further down the pipe. Vinegar can only do the first. It is also odourless, food-approved, solid (so it can be weighed out exactly), and in practice stable in storage for ever if it is kept dry.

CaCO3 + 2 H3Cit → Ca(H2Cit)2 + H2O + CO2↑

Use it for

  • Descaling coffee makers, espresso machines, kettles, steam generators, irons.
  • Maintenance washes of dishwasher and washing machine: 100 g in the empty machine at 60–90 °C.
  • Shower heads and mixer taps — put them in a bag with the solution, tie it on, leave it.
  • Glass shower screens — the limescale film that will not come off with washing-up liquid.
  • Toilet — limescale and urine scale. Leave it overnight.
  • Passivating stainless steel after welding, grinding or machining. 10 % at 60 °C for 30 min builds the chromium oxide layer back up.
  • Alkaline battery leakage in battery compartments and remote controls. The white stuff that leaks out of alkaline cells is potassium hydroxide — it should be neutralised with acid, not washed with soda ash.
  • Neutralising caustic residues after oven cleaning or drain clearing.
  • Mild rust stains on textiles and porcelain, by chelation rather than by dissolution.
  • Milkstone in brewing vessels, milk frothers and vacuum flasks.
  • Underfloor heating and heat exchangers — circulate 5 % warm with a pump.
  • pH adjustment in your own mixtures, and as a stabiliser in peroxide solutions.
Avoid on

Marble, limestone, travertine, terrazzo and untreated concrete — all are calcium carbonate and are etched matt within minutes. Also: prolonged contact with aluminium, and enamelled surfaces whose glaze is already damaged.

Never mix with

Household bleach or any other hypochlorite. It gives off chlorine gas.

LimescaleChelatorFood-safePassivatingOdourless

Acetic acid Acetic acid 24 % · household vinegar 12 % · pure 99 % is called glacial acetic acid

CH3COOH CAS 64-19-7
pH 24 %≈ 2.1
pKa4.76
Boiling point118 °C (pure)
FormLiquid
Price~20 SEK/l
Sold byGrocery shop

What it is good and bad at

Everybody has it at home and it works, but it is worse than citric acid at almost everything it is normally used for. It is a weaker acid, it does not chelate, it smells, and acetic acid attacks rubber and EPDM seals and some hoses over time. Where it is unbeatable, on the other hand, is on surfaces you already have it out for and on biological growth, because it is weakly biocidal.

Use it for

  • Urine scale and limescale rings in the toilet.
  • Mould and algae on grouting, window frames, decking — a weak biocidal effect.
  • A substitute for fabric conditioner in the washing machine, 50–100 ml in the conditioner compartment. It neutralises alkaline detergent residues in the fibre.
  • Glass and mirrors together with IPA.
  • Stickers — soak the paper, and the vinegar works its way into the adhesive.
  • Smells in drains and on the washing-up brush, as a cheap quick fix.
Avoid on

Coffee machines and espresso machines with rubber seals — use citric acid instead. Natural stone. Waxed wooden floors. Screens and display coatings.

Never mix with

Household bleach. It gives off chlorine gas — the commonest poisoning accident in Swedish homes. The combination with hydrogen peroxide gives peracetic acid: very effective but corrosive, and it must never be kept in a closed bottle, because the pressure builds up.

LimescaleUrine scaleMouldAlready in the house

Phosphoric acid Rust converter · orthophosphoric acid · found in StarSan and in Coca-Cola

H3PO4 CAS 7664-38-2
pH 10 %≈ 1.5
pKa12.15
Working strength10–25 %
FormLiquid / gel
Price150–250 SEK/l
Sold byPaint and car accessory shop

What it does to rust

The only acid on the list that does not merely dissolve rust but converts it. Red rust (iron oxide) reacts to iron(III) phosphate, a black, hard, water-insoluble layer that stays put, acts as temporary corrosion protection, and makes an excellent ground for paint. The surface turns grey-black when the reaction is finished — that is the receipt for it having gone all the way.

Fe2O3 + 2 H3PO4 → 2 FePO4 + 3 H2O
Not everything called a rust converter is phosphoric acid

Two quite different chemistries sit under the same sign. One is this one: the acid turns the rust into iron phosphate. The other is tannic acid — tannin from plant matter — which chelates the iron into iron tannate, also black, but held in a binder film rather than laid down as a phosphate layer. Biltema's Rostätare (art. 36-189) is that sort: tannic acid 1–2.5 % and lactic acid 1–2.5 % in a talc suspension, and unlike phosphoric acid it is not classified as hazardous at all.

The difference shows in what they are good for. Phosphoric acid also pickles — it takes fallout rust, cleans bright steel and dissolves limescale. A tannin product does one thing only: it converts the rust it is painted onto and seals it. Read the ingredients rather than the sign if you are buying instead of mixing.

Use it for

  • Rust treatment before painting — chassis, frames, tools, garden furniture, car bodywork.
  • Etching a bright steel surface to give the paint a key.
  • Flash rust on freshly machined steel, and on stainless that has picked up iron contamination.
  • Limescale and rust stains in the bathroom, where citric acid is not enough.
  • Disinfection without rinsing — StarSan is phosphoric acid with a surfactant, 1.5 ml/l, 30 seconds' contact, and the foam is left on. Useful outside brewing too.
  • Milkstone and protein deposits in combination with hot water.
How to work

Brush off loose flakes first — the acid is meant to reach solid rust, not eat its way through layers of loose muck. Gel on a vertical surface. 15–30 minutes, keep it damp. Wipe off, rinse with a little water, dry, and prime the same day. The phosphate layer draws moisture and starts rusting again within a day if it is left untreated.

Avoid on

Zinc-plated and galvanised — the acid eats the zinc, which is exactly the corrosion protection you want to keep. Aluminium (it discolours). Natural stone and concrete. Chromed surfaces.

RustBefore paintingCarDisinfection

Oxalic acid Acid of sorrel · salt of sorrel · wood bleach

H2C2O4·2H2O CAS 6153-56-6 (dihydrate)
pH 5 %≈ 1.0
pKa11.25
Working strength4–8 %
ToxicityLD50 ≈ 375 mg/kg
Price150–300 SEK/kg
Sold byPaint shop, beekeeping supplier

The specialist in iron

Oxalic acid forms a soluble complex with trivalent iron. That means it can remove rust stains that sit inside a material — in wood fibres, in concrete pores, in textiles — where other acids only dissolve the surface. It bleaches lignin at the same time, which is why it restores greyed wood to a light colour without raising the fibre the way bleach does.

Use it for

  • Greyed decking, boards and garden furniture — the classic application. 5 % warm, scrub it in, leave for 20 min, rinse very copiously.
  • Iron stains in oak from nails, screws and fittings (tannic acid + iron gives blue-black).
  • Rust stains on concrete, stone and tile from furniture legs and reinforcement.
  • Rust stains in textiles that will not come out with anything else.
  • Rust removal on tools — soak in 5 % for a few hours.
  • Bleaching wood before oiling or liming.
  • Cleaning radiators and brass in brief contact.
Danger

Toxic if swallowed. The body converts oxalate to calcium oxalate, which precipitates in the kidneys. Nitrile gloves and safety glasses are not optional here. Do not raise dust with the powder — weigh it out of doors or under extraction. Keep it locked away if there are children in the house. Neutralise spills and residues with lime or soda ash before they are flushed away.

Avoid on

Galvanised fittings and screws on the decking — cover them. Marble and limestone. Never mix with bleach.

Finishing off

Residues of oxalic acid in wood interfere with the adhesion of both oil and lacquer. Rinse until the surface feels neutral, and let it dry completely — two days for preference — before you oil it.

Rust inside a materialWoodDeckingToxicBleaching

Sodium bisulfate Sodium hydrogen sulfate · sold as “pH minus” or “pH reducer” for swimming pools

NaHSO4 CAS 7681-38-1
pH 5 %≈ 1.2
pKa1.99
Solubility28 g/100 ml
FormGranules
Price50–70 SEK/kg
Sold byPool supplier, builders' merchant

Sulphuric acid you can keep in a cupboard

The bisulfate ion is sulphuric acid that has given up its first proton and is holding on to the second. What is left is a dry salt that behaves like a strong acid as soon as it dissolves — stronger than citric and phosphoric acid, in the same country as sulfamic acid — but that is stored like caster sugar. No vapour to corrode the tools next to it, no drum that can split, no shelf life to keep track of.

Pool suppliers sell it in three- and seven-kilo sacks for lowering the pH in pools, at a price per kilo no chemical supplier comes close to. It is the same substance.

Use it for

  • Limescale and rust where citric acid is too weak and you do not want to get the hydrochloric acid out.
  • Pickling steel before painting or galvanising.
  • Lowering pH in a solution exactly, on a scale, without pipetting acid.
  • Toilet and urinal with a hard deposit — it works as a dry powder on a damp surface.
  • Cement haze and mortar residues, diluted.
Never mix with

Bleach, shock chlorine, chlorine tablets or anything else that gives off chlorine. Dry powder against dry powder is not harmless: moisture in the air is enough to start the reaction, and the pool store is precisely the place where the two stand side by side.

Avoid on

Aluminium, galvanised, natural stone, concrete. The sulfate ion attacks cement more slowly than it looks as though it does — it shows up only after a season.

See also

The same shelf sells soda ash as “pH plus” and bicarbonate as “alkalinity plus”. Three of the four pH products in the pool aisle are therefore already in this cupboard under other names — only the label is new.

Dry strong acidCheap by the kiloUnlimited shelf lifeChloride-free

Sulfamic acid Amidosulfonic acid · often sold as “heavy-duty descaler”

H3NSO3 CAS 5329-14-6
pH 5 %≈ 0.8
pKa0.99
Working strength3–10 %
FormCrystalline powder
Price120–200 SEK/kg
Sold byPlumbers' merchant, brewing supplier

The strength of hydrochloric acid without its problems

Nearly as strong as hydrochloric acid but supplied as a dry, odourless salt. That means no corrosive vapours in the workshop, exact dosing on a scale, and a long life on the shelf. It contains no chlorides, which makes it the right choice on stainless steel — where hydrochloric acid causes pitting. This is the descaler used in industrial heat exchangers for exactly that reason.

Use it for

  • Heavy limescale where citric acid gives up: water heaters, heating coils, pool equipment.
  • Stainless vessels and tanks that have to be descaled without chloride exposure.
  • Cement haze on newly laid tile and wall tile, diluted to 3 %.
  • Restaurant-grade coffee machines and professional espresso machines.
  • Toilet and urinal with a hard deposit.
Never mix with

Bleach or any other hypochlorite. The combination forms nitrogen trichloride, a compound that is both toxic and shock-sensitive. This is more dangerous than the usual chlorine gas warning and applies even to small amounts. Keep them in different parts of the cupboard.

Avoid on

Galvanised, aluminium, cast iron, natural stone. It must not be kept in contact with nitrates.

Heavy limescaleSafe on stainlessOdourlessDry salt

Hydrochloric acid Hydrogen chloride in water · technical grade 30 % · muriatic acid

HCl (aq) CAS 7647-01-0
pH 10 %≈ 0
StrengthStrong acid
Working strength3–10 %
FormLiquid, fuming
Price~80 SEK/l
Sold byBuilders' merchant

The last resort, not the first choice

This is the only entry in the document I would advise against buying unless you have a concrete need for it. It is fast and cheap, but the vapours spread through the whole room and corrode everything made of iron on the shelves around — tools, machine screws, electrical enclosures. Sulfamic acid does almost the same job without the vapours.

Use it for

  • Cement and mortar residues on tile, stone and masonry.
  • Extremely hard limescale in drains and wells.
  • Etching a concrete floor before an epoxy coating.
  • Pickling steel before galvanising.
Danger

Always dilute by pouring acid into water, never the other way round. Respiratory protection with an E filter, or work outdoors. The vapours corrode tools several metres away. Never mix with bleach — chlorine gas is given off immediately. Do not mix with hydrogen peroxide.

Avoid on

Stainless steel — the chlorides cause pitting that is invisible until the hole is there. Aluminium. Galvanised. Marble, limestone, terrazzo. Coloured grout.

CementExtreme limescaleVapoursOutdoors only

Ascorbic acid Vitamin C · E300 · both an acid and a reductant

C6H8O6 CAS 50-81-7
pH 5 %≈ 2.4
pKa14.17
RoleMild reduction
FormWhite powder
Price200–350 SEK/kg
Sold byBrewing supplier, pharmacy

The gentle option

It reduces trivalent iron to divalent, which is colourless and water-soluble. The effect is the same as oxalic acid's but very much milder — and entirely harmless. When you have a rust stain on something delicate and do not want to risk the material, this is the first thing to try.

Use it for

  • Rust stains on light textiles, porcelain and plastic.
  • Iodine stains — the colour goes almost immediately.
  • Discolouration on stainless from water and heat.
  • Neutralising chlorine in water, before filling an aquarium or watering plants, for instance.
  • An antioxidant in your own mixtures that would otherwise go brown.
  • Photographic development — ascorbate is the active component in Caffenol.
Rust stainsHarmlessReductionTextiles
03

Alkalis

Against everything organic: fat, oil, protein, soot, skin oil, food residue. This is also where the single most important upgrade to your present cupboard lies.

Bicarbonate of soda Sodium hydrogen carbonate · E500(ii) · baking soda · sold as “alkalinity plus” for swimming pools

NaHCO3 CAS 144-55-8
pH saturated8.3
HardnessMohs 2.5
Decomposition> 50 °C in water
FormWhite powder
Price30–60 SEK/kg
Sold byGrocery, pharmacy, pool supplier

Three properties in one tub

Bicarbonate is weakly alkaline, very soft as an abrasive (Mohs 2.5 — softer than glass, paint, chrome and most metals) and a buffer that captures acidic odour molecules. The combination makes it oddly useful, but it is also weak. If you need real degreasing you should use soda ash, not bicarbonate. Heat a bicarbonate solution above 50 °C and it also converts slowly to soda ash and gets stronger.

Baking soda, soda ash and soda water are three different things

The name baking soda means bicarbonate, this substance. What this document calls soda ash is sodium carbonate, a much stronger alkali. Soda water is carbonated drinking water and belongs in no recipe here. Where a recipe in this document says “soda ash”, anhydrous sodium carbonate is always what is meant.

Use it for

  • Gentle scouring on pans, ceramic hobs, baths, plastic and paint — where an ordinary scouring powder would scratch.
  • Odour absorption in the fridge, shoes, bin, car, sports bag. It works on acidic smells (sweat, food, milk) but not on all of them.
  • Neutralising acid spills — including lead-battery acid in the workshop. Sprinkle it on generously, wait until it stops fizzing, wipe it up.
  • Silver polishing in combination with aluminium foil, see recipe 18.
  • Soda blasting for soft substrates: the only blasting medium that takes paint off without damaging the panel underneath.
  • Putting out a fat fire in the pan — it smothers with carbon dioxide. Never water.
  • Grill grates and oven trays, as a paste: 3 parts bicarbonate to 1 part water, spread it on, leave it an hour, rub it off.
  • Boosting detergent and stabilising the pH of the wash water.
  • Foot baths, insect bites and formic acid stings, as a mild base.
What it cannot do

Burnt-on fat, hardened oil in extractor filters, oven spills. Those need soda ash or caustic soda. It also stops working entirely if you mix it with vinegar: you get sodium acetate and a lot of bubbles, that is, a neutral salt with no cleaning action. That combination is household chemistry's most widely held misunderstanding.

Mild abrasionOdourNeutralisingFood-safe

Washing soda & soda ash Sodium carbonate · washing soda · soda ash · E500(i) · sold as “pH plus” or “pH increaser” for swimming pools

Na2CO3·10H2O CAS 6132-02-1 · anhydrous 497-19-8
pH 1 %≈ 11.2
Active content37 % (crystals)
Working strength10–50 g/l
FormCrystals / powder
Price30–70 SEK/kg
Sold byGrocery, builders' merchant, pool supplier
Read this before you measure anything out

Washing soda and soda ash are not the same thing. Washing soda is the decahydrate and contains 63 % water of crystallisation — only 37 % is working sodium carbonate. Anhydrous soda ash (pool soda) is essentially 100 %. 1 part anhydrous soda ash ≈ 2.7 parts washing soda crystals. Almost every recipe online is careless about this, which is why home-made mixtures often come out a third of the strength intended.

In this document “soda ash” always means the anhydrous kind wherever a quantity is given. It is not soda water — carbonated water — and it is not bicarbonate either, which is sold as baking soda. Three different things, three entirely different results: pH 11.2 against pH 8.3 against nothing at all.

What it does

Three things at once. It raises the pH enough to saponify fat — to break the ester bonds in triglycerides so that the fat becomes water-soluble. It softens the water by precipitating calcium as the carbonate, so that the surfactant is not used up on lime soap. And it builds alkalinity, that is, it holds the pH up while the dirt consumes base. That is why soda ash is the basis of practically every industrial cleaning powder.

Use it for

  • Extractor filters and cooker hoods — soak them in the sink, 50 g/l in the hottest water the tap gives, 30 min. The hardened fat falls off without scrubbing. One of the most satisfying household tricks there is.
  • Oven trays, grill grates, frying pans with burnt-on fat.
  • Pre-treating laundry — collars, cuffs, work clothes, oil stains.
  • Boosting detergent in hard water, 1–2 tbsp in the drum.
  • Degreasing before painting and bonding.
  • Decking, fences and cladding — the rough wash before an oxalic acid treatment.
  • Drain maintenance: 100 g of anhydrous soda ash followed by 2 l of boiling water once a month keeps fat blockages away without caustic soda.
  • Cleaning tools and machine parts in a warm bath.
  • Raising the pH in a pool, and as the alkali source in your own formulations.
  • Electrolytic rust removal — soda ash as the electrolyte, 20 g/l, a sacrificial anode of reinforcing bar, 5–12 V DC. It takes rust out of threads and cavities no brush can reach.
Avoid on

Aluminium — soda ash etches and discolours aluminium within minutes, and an aluminium pan with soda solution in it goes permanently black. This applies to unpainted alloy wheels and pans with an aluminium core as well. Also: painted and oiled wood, linseed oil paint, wool, silk, natural stone containing lime.

FatSaponificationWater softenerCheapNot on aluminium

Sodium metasilicate Water glass in solid form · a component of PBW and of industrial degreasers

Na2SiO3 CAS 6834-92-0 · pentahydrate 10213-79-3
pH 1 %≈ 12.5
RoleAlkali + inhibitor
Working strength5–20 g/l
FormBeads / powder
Price100–180 SEK/kg
Sold byBrewing supplier, chemical supplier

Niche but underrated

The silicate does two things soda ash cannot. It is a considerably stronger degreaser at the same dose, and it lays down a thin silicate film on aluminium, zinc and light alloys that protects them from the alkali itself. That is why professional degreasers for engines and wheels contain silicate: you get alkaline strength without sacrificing the light metal. It is also one half of PBW, the brewing industry's standard cleaner — the other half is sodium percarbonate.

Use it for

  • Your own PBW — see recipe 12. It dissolves burnt-on organic matter without scrubbing.
  • Engine and machinery degreasing where aluminium parts must not be attacked.
  • Oven cleaning as a milder alternative to neat caustic soda.
  • Concrete and stone floors, oil stains in the garage — see recipe 28.
  • Heavy degreasing before painting on steel.
  • A corrosion inhibitor in your own alkaline mixtures; 1–3 g/l is enough.
Things to bear in mind

Corrosive to skin and especially to eyes. Rinse thoroughly — silicate residues that dry on leave a film that is troublesome to remove and that interferes with paint adhesion. It must not be mixed with acid: the silicate precipitates as silica gel.

Heavy degreasingProtects aluminiumPBW

Household ammonia Ammonia solution 5–10 % · ammonium hydroxide

NH3 (aq) CAS 1336-21-6
pH 5 %≈ 11.7
pKb4.75
PropertyVolatile
FormLiquid, pungent
Price40–70 SEK/l
Sold byPaint shop, builders' merchant

The only base that evaporates

Every other alkali leaves a salt behind when the water dries. Ammonia disappears into the air. That is the whole point: you get alkaline degreasing on a surface that has to end up completely streak-free, and you do not need to rinse afterwards. It is therefore unbeaten on windows, mirrors and glass, and it is why it appears in every professional window-cleaning formula.

Use it for

  • Windows, mirrors, glass doors — see recipe 08.
  • Stainless worktops and white goods that have to come out streak-free.
  • Grease stains on textiles and carpets, diluted 1:10.
  • Reviving carpet fibres that have been trodden flat.
  • Cleaning gold jewellery, diluted, a short bath. Not pearls, opal, coral or glued-in stones.
  • Degreasing before bonding on metal and glass.
  • Removing ceramic glaze marks and water marks on glossy surfaces.
Brass and copper

Ammonia causes stress corrosion in brass — the alloy cracks along the grain boundaries, often only several days later, and the crack is invisible until the part breaks. This is not a theoretical risk: it is the classic failure mechanism behind broken brass fittings. Keep ammonia away from brass nipples, valves, instruments and brass wind instruments. It attacks copper and copper alloys as well.

Never mix with

Bleach. It gives off chloramines — a toxic gas, and one of the commonest serious domestic poisonings. The combination usually arises by accident, when two different cleaning products are used one after the other on the same surface.

Avoid on

Painted and oiled wooden floors, linseed oil paint, waxed surfaces, screens with anti-reflective coatings, aluminium.

WindowsStreak-freeVolatileNot on brass

Sodium hydroxide Caustic soda · lye · drain opener

NaOH CAS 1310-73-2
pH 1 %≈ 13.4
Heat of solution44.5 kJ/mol
Working strength2–10 %
FormBeads / flakes
Price60–120 SEK/kg
Sold byBuilders' merchant, paint shop

The heavy end

Caustic soda dissolves fat by complete saponification — it breaks the triglyceride down into glycerol and soap. It is the same reaction that makes soap, except that here it happens in the drainpipe or on the oven floor. What makes caustic soda special is that it also attacks protein and hair, which soda ash does not, and that it works on hardened and polymerised oils that are immune to anything milder.

fat + 3 NaOH → glycerol + 3 fatty acid salts (soap)   — irreversible

Use it for

  • Drain blockages of fat and hair, 50–100 g straight into the pipe followed by hot water.
  • Oven cleaning — see recipe 07. Every commercial oven-cleaning spray is caustic soda with a surfactant.
  • Deep-fryer fat and burnt-on oil in stainless or cast iron vessels.
  • Stripping paint from wood and the traditional liming of floors and furniture.
  • Soap making, cold or hot process.
  • Etching aluminium before anodising — here the attack is the point.
  • Cleaning cast iron pans that are to be re-seasoned from scratch.
  • Neutralising acid residues on a large scale.

Making your own caustic soda — and why you should not

Caustic soda was made for centuries by causticisation: soda ash and slaked lime in water, whereupon calcium carbonate precipitates and leaves sodium hydroxide behind in solution.

Na2CO3 + Ca(OH)2 → 2 NaOH + CaCO3↓

The reaction works, and both ingredients are on the shelf in any builders' merchant. But the result is a solution of unknown strength — you do not know whether you got 2 % or 8 % without titrating — and it cannot be dried down to beads at home: evaporated caustic soda takes up carbon dioxide from the air and turns back into soda ash, and boiling down a corrosive solution is exactly as bad as it sounds. The end product is as corrosive as the bought kind, weaker, and the raw materials cost about what ready-made caustic soda costs. This is an experiment, not a saving.

The electrolysis route: never

The other method is electrolysis of brine. It gives caustic soda at the cathode — and chlorine gas at the anode, together with hydrogen. Which is to say exactly the gas the whole mixing table is about avoiding, made on purpose, in a garage, next to something explosive. Do not do this.

Handling
  • Always caustic soda into water, never water into caustic soda. 100 g in a litre raises the temperature by about 25 °C. Concentrated, it can boil over and spit.
  • Use PP or HDPE vessels. Never aluminium, never glass that can crack from the heat.
  • Close-fitting goggles, not safety spectacles. Caustic soda causes irreversible eye damage faster than acid does, because it saponifies the cornea instead of coagulating the surface.
  • Nitrile gloves. Caustic soda feels slippery on the skin — that is your own skin oil being saponified. Rinse at once and for a long time.
Hydrogen

Caustic soda + aluminium, zinc or tin gives hydrogen. In a stoppered bottle or a sealed drain that means pressure and a flammable gas mixture. Never caustic soda in an aluminium pan, and never caustic soda on top of an agent already standing in the drain.

Hardened fatDrainsOvenCorrosiveNot on light alloys
04

Oxidants

Against coloured stains, microbial growth and discoloured material. Oxidants do not remove dirt — they break apart the double bonds that make the dirt visible.

Sodium percarbonate Oxygen bleach · “oxi” · PBS · solid hydrogen peroxide

2Na2CO3·3H2O2 CAS 15630-89-4
pH 1 %≈ 10.5
H₂O₂ equiv.≈ 27 % by weight
Working temp40–70 °C
FormWhite granules
Price60–120 SEK/kg
Sold byBrewing supplier, janitorial supplier
The most important upgrade to your cupboard

This is dry hydrogen peroxide. Dissolve 100 g in a litre of warm water and you get roughly the equivalent of 275 ml of 10 per cent peroxide plus the soda ash that makes the peroxide actually work — an alkaline pH is what activates it. The difference from liquid peroxide is the shelf life: the powder sits stable for years in a sealed tub, while your 3 per cent bottle loses strength continuously and is often nearly useless after a year.

How it works

The percarbonate is an addition complex — the peroxide sits bound into the soda crystal and is released only in water. The reaction is sluggish below 40 °C and effective at 60 °C. The half-life in solution is hours, not days, so the mixture should be made fresh every time.

2Na2CO3·3H2O2 → 2Na2CO3 + 3H2O2   (in water)

Use it for

  • Stains in textiles — wine, coffee, blood, grass, sweat, discoloured whites. 20 g/l, 60 °C, soak 1–6 hours.
  • Decking, patios, fences and cladding — it takes algae, moss and greying off without raising the fibre the way bleach does.
  • Coffee pots, vacuum flasks and mugs with a deposit.
  • Bathroom grouting — as a paste, percarbonate and water in equal parts, covered with cling film for 2–4 hours. See recipe 24.
  • Brewing and fermentation vessels, the main component of PBW.
  • Chopping boards and plastic utensils that have discoloured.
  • Retrobright — the peroxide source for de-yellowing yellowed ABS plastic on old computer equipment, see recipe 22.
  • Plastic garden furniture and white window profiles.
  • Drains and sources of smell — the oxygen breaks the sulphur compounds apart.
Avoid on

Wool, silk and other protein fibres — both the alkali and the oxidant destroy them. Aluminium (the soda ash). Stained wood and dyed surfaces. Leather. Always test on coloured textiles.

Storage

Moisture-sensitive. A tub that has taken up humidity slowly begins giving off oxygen and can build pressure. Keep the lid tight, store it dry, and never mix it in a closed bottle. It must not be mixed with bleach or with acid.

StainsBleachingAlgaeStable in storageRetrobright

Hydrogen peroxide 3 % pharmacy · 12 % hair bleach (“40 vol”) · stronger needs a licence

H2O2 CAS 7722-84-1
pH 3 %≈ 4.5
DecompositionLight, Fe, Cu, Mn
Shelf life6–18 months once opened
FormLiquid / cream
Price50–200 SEK/l
Sold byPharmacy, hairdressing wholesaler

Why your bottle stopped working

Hydrogen peroxide decomposes to water and oxygen, and the decomposition is strongly catalysed by iron, copper and manganese ions — that is, by tap water, by metal surfaces and by dust. Light and heat speed it up. An opened bottle of 3 % that has stood a year in the bathroom cabinet may be down to a single per cent. Two counter-measures: store it dark and cool, and add a chelator (citric acid or EDTA) to your own mixtures to catch the metal ions.

Use it for

  • Retrobright on yellowed ABS. 12 % is the standard strength, see recipe 22.
  • Wound cleaning — 3 %, but only on genuinely dirty wounds; peroxide damages healthy tissue too and delays healing with repeated use.
  • Blood and protein stains on light textiles; it works immediately at room temperature.
  • Mould on grouting and silicone, 6 % with a little thickener.
  • Disinfection of chopping boards, washing-up brush and bin area.
  • Smells in laundry — it breaks down the sulphur compounds in towels and sportswear.
  • Cleaning a PCB after soldering together with IPA where the residues are thick.
  • Bleaching bone, horn and wood in hobby work.
At higher concentrations

12 % gives white chemical blisters on skin within seconds — they sting, they go away after an hour, but it is a real chemical burn. Gloves, always. Never mix concentrated peroxide with acetone. Never mix it with bleach. Never store a peroxide mixture in a tightly closed bottle.

12 % is a legal limit, not just a practical one

Hydrogen peroxide above 12 per cent by weight is an explosives precursor restricted under EU Regulation 2019/1148. Private individuals may not acquire, import, possess or use it without a licence — in Sweden that licence comes from MSB, and some member states ban it outright instead. Hair bleach's “40 volume” sits at exactly 12 % and is therefore the strongest you can buy freely, which is also the strength the recipes here are written for. See the section on regulation.

BleachingDisinfectionRetrobrightShort shelf life

Household bleach Sodium hypochlorite · bleach · on the list so that you know where it should not be

NaOCl CAS 7681-52-9
pH≈ 12.5
Available chlorine3–5 % household
Shelf life6 months, weak after that
FormLiquid
Price~30 SEK/l
Sold byGrocery

An agent that makes everything else in the cupboard dangerous

Bleach is effective, but it is also the only entry in this document that is incompatible with practically everything else: with acids it gives chlorine gas, with ammonia chloramines, with sulfamic acid nitrogen trichloride, with peroxide a violent evolution of oxygen. Since the incidents nearly always arise by accident — two agents one after the other in the same toilet — the recommendation is simple: use sodium percarbonate instead. It does 90 % of the same job, has no smell, does not bleach colours, does not destroy grouting, and is compatible with the rest of the cupboard.

The few cases where it is justified

  • Black mould on non-porous surfaces, where nothing oxygen-based is enough.
  • Disinfection after a drain flood or when clearing up after an infection.
  • Pools, in the system designed for it.
If you keep it

Store it physically apart from acids, ammonia, percarbonate and peroxide — a different shelf, preferably a different room. Never pour bleach into a toilet where you have just used an acidic agent. Write the date on the bottle; after six months it is considerably weaker than the label claims.

Black mouldIncompatible with everythingCan be replaced

Calcium hypochlorite “Shock chlorine” · chlorine granules · hypocal · inorganic chlorine

Ca(ClO)2 CAS 7778-54-3
pH 1 %≈ 11
Available chlorine65–70 %
Shelf lifeYears, stored dry
Solubility21 g/100 ml
Price~100 SEK/kg
Sold byPool supplier

Bleach that does not go quiet on the shelf

A bottle of household bleach has lost a large part of its strength after six months, and the label says nothing about it. Calcium hypochlorite is the same chlorine chemistry in solid form and sits for years without weakening. Fifteen grams in a litre of water gives a solution stronger than the bleach ever was, mixed on the day you need it.

What is left over is calcium, which is the whole point in a pool with soft water and entirely beside the point when you are disinfecting a floor drain. The solution goes cloudy for the same reason.

Use it for

  • Disinfection where you want a known strength, not a guess out of an old bottle.
  • An emergency store — the only source of chlorine that makes sense to keep for a long time.
  • Black mould on non-porous surfaces, where oxygen-based is not enough.
  • Pools, in the system designed for it, as shock chlorination.
Never mix with

Chlorine tablets of trichloroisocyanuric acid. Both are called “chlorine” and often stand in the same store, but together they form nitrogen trichloride and can ignite or explode — which is why they are shipped separately. Nor acid, ammonia, urea or oil: granules that land in an oily rag can self-ignite.

Storage

Cool, dry, in the original tub and not in a metal cupboard. Moisture and heat start a slow decomposition that gives off both chlorine gas and pressure in the container.

Solid chlorineLong shelf lifeStrong oxidantUnstabilised

Trichloroisocyanuric acid TCCA · chlorine tablets · chlorine pucks · “slow-release chlorine” · organic chlorine

C3Cl3N3O3 CAS 87-90-1
pH 1 %≈ 2.8
Available chlorine90 %
Shelf lifeSeveral years
Solubility1.2 g/100 ml
Price~100 SEK/kg
Sold byPool supplier

On the list for the sake of the hazard

The highest chlorine content on the shelf, 90 %, in tablets that keep for years and dissolve so slowly that one puck lasts a week. The low solubility is the whole design: chlorine is given off at the rate the water can manage to dissolve the tablet.

Outside a pool it still has few uses — it is acidic in solution, it leaves cyanuric acid behind, and for disinfection in the home calcium hypochlorite does the same job more simply. The reason to know it is that it looks like an innocent white tablet and stands next to the thing it absolutely must not be mixed with.

Two chlorine products that must never meet

TCCA plus calcium hypochlorite gives nitrogen trichloride, fire or explosion. The trap is that both are called “chlorine” in the store and feel interchangeable. They are chemically opposite: one is organically bound chlorine, the other inorganic. Do not mix them, do not pour them into the same bucket, and do not use the same scoop for both without rinsing in between.

Also

Moisture slowly releases chlorine gas from the tablet — store it dry and sealed. With ammonia, ammonium salts or urea, nitrogen trichloride forms here too.

Highest chlorine contentVery long shelf lifeIncompatible with shock chlorine
05

Reductants

The opposite of the oxidants, and the category almost nobody has at home. They remove stains that were caused by oxidation — and they clear up after your own oxidants.

Sodium metabisulfite E223 · “sulfite” · Campden tablets are the same thing in tablet form

Na2S2O5 CAS 7681-57-4
pH 5 %≈ 4.3
ReleasesSO2
Working strength1–20 g/l
FormCrystalline powder
Price80–150 SEK/kg
Sold byBrewing supplier

The cleaner-up after the oxidants

Metabisulfite grabs oxygen. That makes it the antidote to chlorine and peroxide residues, and the answer to a class of stains nothing else can touch: the ones that arose through oxidation. A yellow patch in white cloth after too harsh a bleach, browned wood, discoloured plastic — the reductant can bring them back from where the oxidant will never reach.

Use it for

  • Neutralising chlorine in water, in a pool, in the wash and after disinfection.
  • Stopping a peroxide treatment that has gone too far.
  • Oxidation stains in textiles that bleach only makes worse.
  • Disinfecting brewing equipment, 20 g/l as a sterilising solution.
  • Preserving juice, wine and jam on a hobby scale.
  • Removing permanent dye and discolouration in textiles.
  • Reducing discoloured silver and copper, as a milder alternative to acid.
Sulphur dioxide

An acid environment releases SO2 — a pungent gas that triggers asthma. Do not mix it with acid in a closed space, and work with ventilation. Asthmatics should avoid it altogether. Never mix it with bleach.

See also

Ascorbic acid under Acids is a milder reductant for the same sort of problem, and entirely harmless. Always try that one first.

Chlorine neutralisingOxidation stainsDisinfection

Sodium thiosulfate Fixer salt · antichlor · “hypo” · sold as a dechlorinator for aquariums

Na2S2O3·5H2O CAS 10102-17-7
pH≈ 7.5
Solubility70 g/100 ml
Melts48 °C
FormCrystals
Price200–300 SEK/kg
Sold byAmazon, aquarium shop

The reductant that does not smell

Thiosulfate does the same thing as metabisulfite — grabs chlorine and reduces it to harmless chloride — but without the sulphur dioxide. That is the difference that decides which one you reach for indoors, and it is the only one of the two an asthmatic can use.

4 NaClO + Na2S2O3 + 2 NaOH → 4 NaCl + 2 Na2SO4 + H2O

The crystals melt at 48 °C in their own water of crystallisation, which is unexpected but only means that a bag left in the sun becomes a lump. It works the same once dissolved.

Use it for

  • Dechlorinating tap water for aquariums, plants and fermentation.
  • Neutralising a bleach spill before you wipe it up, instead of diluting it further.
  • Stopping iodine stains — thiosulfate decolourises iodine immediately.
  • A fixing bath in black-and-white photography, which is the same substance and the same reaction.
  • Emptying pool water into a storm drain without killing everything in the ditch.
With acid

An acid environment breaks the thiosulfate down into sulphur dioxide and a precipitate of yellow sulphur. Harmless on a small scale, but the solution goes cloudy and smells — do not pour acid into it.

See also

Metabisulfite above is cheaper and easier to get hold of at a brewing supplier, but it gives off SO2. If the space is cramped or somebody in the household is asthmatic, take thiosulfate.

Chlorine neutralisingOdourlessFixer saltIodine
06

Solvents

Here pH does not matter. What decides is polarity: a solvent dissolves what resembles itself. Arranged from polar to non-polar.

Common to the whole category

Every entry below is flammable, several of them in class 1. No naked flame, no soldering iron, no static discharge in a closed workshop. Ventilate. Rags soaked in solvent go into an airtight tin or are dried outdoors — rolled up in a wastepaper basket they can self-ignite, especially if they also contain linseed oil. Nitrile gloves are dissolved by acetone; change gloves often, or use butyl rubber for longer work.

Isopropanol IPA · isopropyl alcohol · 99.5 % or 70 %

C3H8O CAS 67-63-0
Boiling point82.6 °C
Flash point12 °C
PolarityMedium-high
Water-solubleCompletely
Price100–200 SEK/l
Sold byElectronics supplier

99.5 % or 70 %?

For electronics and optics: 99.5 %. The water in the 70 per cent kind leaves residues, takes longer to dry and can corrode. For disinfection: 70 %. It sounds back to front, but water is needed to denature the bacterium's proteins, and the slower evaporation gives a longer contact time. Neat alcohol coagulates the surface and leaves the cell alive underneath.

Use it for

  • Circuit boards and flux residues after soldering, with a brush or an ultrasonic bath.
  • Degreasing before bonding, taping or soldering.
  • 3D printer beds of PEI or glass — the standard clean between prints, and for washing resin prints.
  • Thermal paste — the only right way to get old paste off a CPU and heatsink.
  • Optics and camera lenses, with the right cloth and a light hand.
  • Marker pen and whiteboard residues on almost any surface.
  • Adhesive residues — it works reasonably, but petroleum spirit is better.
  • Screens, heavily diluted (1:3) and on a cloth, never straight onto the screen.
  • De-icing locks and screen wash in your own mixture.
  • A drying aid after cleaning electronics with water — it drives out residual moisture.
Avoid on

Polycarbonate and acrylic (PMMA). IPA does not dissolve them, but it causes stress cracking — a fine net of crazing that appears hours or days later on parts with internal stresses. This applies to visors, safety glass, LED lenses, transparent covers and 3D-printed PC parts. Also avoid it on anti-reflective coated optics, printed symbols on plastic, rubber seals and leather.

ElectronicsDegreasingFast-dryingNot polycarbonate

Acetone Propanone · dimethyl ketone · nail varnish remover

C3H6O CAS 67-64-1
Boiling point56 °C
Flash point−20 °C
PolarityMedium
Water-solubleCompletely
Price80–150 SEK/l
Sold byPaint shop, builders' merchant

Powerful and indiscriminate

Acetone dissolves most things organic, including the plastics you are working on. That is both its strength and its entire problem. The rule is simple: test on a hidden surface first, every time, even if you have done it before on something that looked the same.

Use it for

  • Uncured epoxy and polyester — cleaning tools, mixing vessels and brushes before the cure has started. After it has cured, nothing works.
  • Bonding ABS — acetone dissolves the surface and the parts weld together. Acetone + ABS scraps gives a slurry that works as filler and adhesive in 3D printing.
  • Vapour polishing ABS prints in a closed container.
  • Nail varnish, cured lacquer and paint splashes on glass and metal.
  • Degreasing where IPA is not enough — resins, oils, waxes.
  • Superglue on fingers, hard surfaces and wherever it has ended up by mistake.
  • Cleaning a solder paste stencil and SMD tools.
  • Removing marking paint and screen printing from metal.
It dissolves

ABS, polystyrene, polycarbonate, PVC, PMMA, most lacquers, many rubber and synthetic textiles, and nitrile gloves. Never on car paint, lacquered wood, painted surfaces, instrument panels or screens.

Never mix with

Concentrated hydrogen peroxide, and particularly not with acid present. The combination forms an unstable peroxide compound. This should never be done, on any scale.

EpoxyABSLacquerAggressiveTest first

Ethyl acetate Acetic ester · “acetone-free” nail varnish remover

C4H8O2 CAS 141-78-6
Boiling point77 °C
Flash point−4 °C
PolarityMedium-low
OdourSweet, pear
Price150–250 SEK/l
Sold byChemical supplier, pharmacy

Acetone light

It dissolves roughly the same things as acetone but is very much kinder to plastics and lacquer. When you want acetone's effect on something you dare not expose to acetone, this is the middle step. Above all it is the best agent against cyanoacrylate — ordinary superglue — and the only one that takes cured superglue off without destroying the substrate.

Use it for

  • Cured superglue on skin, plastic, lacquer and metal. Soak it, and be patient.
  • Nail varnish on surfaces that cannot take acetone.
  • Removing ink and marker pen on a delicate substrate.
  • Cleaning optics and prisms in the cases where IPA leaves a film.
  • Degreasing plastic parts before bonding.
SuperglueMilder than acetoneKinder to plastics

Petroleum spirit Cleaning naphtha · lighter fuel · heptane · naphtha · “Ronsonol”

C7H16 among others CAS 142-82-5 · naphtha 8032-32-4
Boiling point60–100 °C
Flash point≈ −4 °C
PolarityNon-polar
Water-solubleNo
Price100–200 SEK/l
Sold byHardware shop, tobacconist
The most underrated bottle in the house

There is no better adhesive remover, and almost nobody has it at home. It dissolves rubber cement and tape adhesive immediately, it evaporates without a trace, and it is safe on car paint, most plastics, glass and lacquered surfaces — exactly the materials that adhesive residues tend to sit on and that acetone would ruin.

Use it for

  • Adhesive and tape residues — labels, price stickers, duct tape, double-sided tape, masking tape that has been left on too long.
  • Asphalt and tar spots on the car. Gentler than commercial tar remover.
  • Wax and underseal.
  • Grease stains in textiles — drop it on the back and let it soak into paper underneath.
  • Silicone grease and old lubricants in mechanisms.
  • Chains, bearings and precision mechanisms — it dissolves old grease without attacking plastic parts or lacquered housings.
  • Ink and printing ink on hard surfaces.
  • Cleaning lacquered and painted surfaces where nothing water-based will bite.
Avoid on

Rubber and rubber seals — they swell. Foam and expanded plastics. Oil paintings. Some vinyl flooring and artificial leather.

Adhesive residuesTarKind to lacquerLeaves no residue

White spirit Turpentine substitute · mineral spirits · brush cleaner

C9–C12 CAS 64742-88-7 · 8052-41-3
Boiling point145–200 °C
Flash point> 38 °C
PolarityNon-polar
EvaporationSlow
Price50–90 SEK/l
Sold byPaint shop

The slowness is the function

Where petroleum spirit evaporates in ten seconds, white spirit stays put for several minutes. On a hard, old, dried-on deposit that is exactly what you need: the contact time does the work. It is also less flammable — a flash point above 38 °C means it does not ignite at room temperature — which makes it more suitable for large areas and longer sessions.

Use it for

  • Brushes and tools after oil paint, alkyd paint and woodstain.
  • Dried-on oil, wax and underseal.
  • Underbody treatment and heavy tar on vehicles.
  • Degreasing engine parts and old machinery.
  • Old labels and adhesive residues that petroleum spirit does not have time to soften.
  • Cleaning and caring for cast iron tools and machine tables.
Self-ignition

Rags with white spirit and linseed oil can self-ignite as the oil oxidises and generates heat. This causes workshop fires every year. Put them in water, in an airtight metal tin, or lay them out flat outdoors until they have dried.

Oil paintWaxLong working timeLess flammable

D-limonene Citrus terpene · orange peel oil · “natural degreaser”

C10H16 CAS 5989-27-5
Boiling point176 °C
Flash point48 °C
PolarityNon-polar
OriginCitrus peel
Price250–450 SEK/l
Sold byHobby chemical supplier

Powerful despite the reputation for being gentle

That it is extracted from orange peel does not mean it is mild — limonene is a strong non-polar solvent that dissolves polystyrene so fast that you can melt expanded polystyrene in it. It is expensive, but it evaporates slowly, smells good and is an effective additive: a couple of per cent in a water-based mixture gives it appreciable grease-cutting power.

Use it for

  • Pitch and resin on tools, saw blades, cars parked under pines, and on hands.
  • Chewing gum in carpets and on asphalt.
  • Stubborn adhesive residues where petroleum spirit dries too fast.
  • Ink and marker pen.
  • A booster in your own agents, 1–5 % with a surfactant as emulsifier.
  • Hand cleaning for workshop dirt, in a paste with sawdust or silica flour.
Two warnings

It dissolves polystyrene, ABS and many rubbers. Oxidised limonene — that is, a bottle that has stood open a long time — forms hydroperoxides that are strongly sensitising. Keep the bottle sealed, store it dark, and throw it away when the smell has gone sharp instead of sweet.

PitchAdhesiveAdditiveSmells good

Methylated spirits Denatured ethanol ≈ 95 % · sold in Sweden as T-röd

C2H6O CAS 64-17-5
Boiling point78 °C
Flash point13 °C
PolarityHigh
PurityDenatured
Price40–70 SEK/l
Sold byGrocery, builders' merchant

Cheap and good — except where it counts

For floors, windows and general cleaning, methylated spirits is excellent and costs a fraction of IPA. But the denaturants — bitrex, MEK, dye — leave residues, and where residues are the problem you should not save money. On circuit boards, optics and contact surfaces: use IPA.

Use it for

  • Floors, windows, general cleaning as a solvent component, 5–10 % in water.
  • Spirit stoves and burners.
  • Antifreeze in screen wash and locks.
  • Heavy degreasing before painting on wood and metal.
  • Removing shellac — ethanol is its only solvent.
Not for

Circuit boards, optics, connectors or anything else where an invisible film matters.

CheapFloorsShellacLeaves residues
07

Surfactants, enzymes and additives

What separates a home-made mixture from a product. An acid or a base dissolves the dirt; it is these substances that make it stay on the surface, lift the dirt and hold it in suspension so that it can be rinsed away — plus the enzymes, which cut apart dirt that neither end of the pH scale can reach without destroying the material.

Alkyl polyglucoside APG · Plantacare, Glucopon, Lauryl Glucoside · non-ionic surfactant

C8–C16 glucoside CAS 68515-73-1 · 110615-47-9
pH-stable2 – 13
TypeNon-ionic
Active content~50 % in the commercial product
Dose1–5 %
Price150–300 SEK/l
Sold byHobby chemical supplier online
Why this surfactant in particular

Most surfactants die in a strongly alkaline or strongly acidic environment — they hydrolyse or precipitate. APG is stable the whole way from pH 2 to pH 13. That means it is the only surfactant you need: the same bottle goes into the caustic soda, into the soda ash, into the citric acid gel and into the peroxide-based mixture. It is also made from sugar and fatty alcohol, completely biodegradable, and mild enough to be used in shampoo.

What a surfactant actually does

The molecule has a water-loving head and a fat-loving tail. It settles at the boundary between the dirt and the water, lowers the surface tension so that the solution can wet the surface instead of beading off it, lifts the fat away from the substrate and encapsulates it in micelles so that it does not settle back. Without a surfactant your soda solution runs off the vertical oven wall without doing anything at all.

Use it for

  • All your own cleaning agents, 1–3 % is nearly always enough.
  • A wetting agent in alkaline baths for degreasing metal.
  • A foam stabiliser in gels and sprays that have to stay on a vertical surface.
  • An emulsifier when you want to mix a few per cent of solvent into water.
  • Garden sprays — a wetting agent so that the solution sticks to waxy leaves.
Alternatives if you cannot find APG

Washing-up liquid can be used as a stopgap, but it contains salt, perfume, dye and anionic surfactants that fare worse at extreme pH. Avoid it in caustic soda and in acid gel.

Alkali-stableAcid-stableBiodegradableUniversal

Enzymes Protease, lipase, amylase, cellulase · “bio” detergents, soaking powders

Protein Works at pH 7–10
Best at30–50 °C
Dies at> 60 °C
pH windowAbout 6–10.5
Dose2–10 g/l
Price200–400 SEK/kg
Sold byBrewing supplier, janitorial wholesaler
This is the answer when both acid and base are the wrong tool

The rest of the document dissolves dirt by moving the pH to an extreme. Enzymes do something else entirely: they cut specific molecules apart at nearly neutral pH and body temperature. That means they can take blood out of silk, egg yolk out of wool and protein deposits out of a plastic part — materials that caustic soda and percarbonate would destroy. It is the only category in the cupboard that is powerful and gentle at the same time.

Four kinds, four kinds of dirt

  • Protease — protein. Blood, egg, milk, sweat, grass, faeces, skin and body fluids. The commonest and most useful.
  • Lipase — fat and oil. Cooking fat, skin oil, sauce, butter. Slower than the others and needs a genuinely long working time.
  • Amylase — starch. Potato, pasta, sauce, chocolate, baby food.
  • Cellulase — cellulose. Not used against stains but to shave off the raised fibre ends on cotton, that is, against bobbling and greyness.

Use it for

  • Blood, sweat and body fluids in textiles — including wool and silk, where percarbonate is out of the question.
  • Nappies, work clothes, gym kit and smells that sit in the fibre.
  • Food residues on dishes, particularly dried-on egg yolk and starch, which alkali bites on poorly.
  • Pet accidents on carpets — protease breaks down the proteins in the urine, which is the only thing that really takes the smell away instead of masking it.
  • Coffee and protein deposits in vacuum flasks and vessels of soft plastic.
  • Pre-treatment before an ordinary wash: paste straight onto the stain, 30 minutes.
Four ways to kill them
  • Too hot. Above 60 °C the enzyme denatures within minutes. Soak at 40 °C, not in boiling water.
  • Too high a pH. Caustic soda and metasilicate knock them out immediately. Soda ash works, just.
  • Oxidants. Percarbonate, peroxide and bleach break the enzyme down. Modern detergents have stabilised variants, but in your own mixture: keep them apart, or soak with enzyme first and bleach in a second step.
  • Too short a time. Enzymes work slowly. Under 20 minutes almost nothing happens; an hour to overnight is where they do their job.
In practice

The simplest source is an enzyme-based soaking powder or a liquid bio detergent — you do not need to buy pure enzymes. If you want them pure: look for protease in powder form at brewing suppliers, where it is sold for cleaning fermentation vessels. Dry enzyme powder keeps for several years; liquid for about one.

ProteinBloodWool and silkOdourGentle

EDTA Ethylenediaminetetraacetic acid · tetrasodium or disodium salt

C10H12N2Na4O8 CAS 64-02-8 (tetra) · 139-33-3 (di)
pH tetra 1 %≈ 11.5
pH di 1 %≈ 4.5
BindsCa, Mg, Fe, Cu, Mn
Dose0.1–2 %
Price200–350 SEK/kg
Sold byHobby chemical supplier, brewing supplier

The tongs that grip metal ions

EDTA wraps itself around a metal ion at six points and makes it chemically invisible. The effects are out of all proportion to the amount: half a per cent in a mixture can more than double its effect in hard water, because the surfactant is not used up precipitating lime soap and the peroxide is not decomposed by iron ions.

Use it for

  • Stabilising hydrogen peroxide in your own mixtures — the single biggest reason home-made peroxide gel does not work is unchelated metal ions.
  • Boosting any cleaning agent in hard water.
  • Rust stains and iron discolouration, in alkaline solution.
  • Lime soap in the shower and the washing machine.
  • Preventing precipitation in your own concentrates that have to stand a long time.
Environment

EDTA breaks down very slowly in nature and can mobilise heavy metals in sediment. Use it sparingly, and switch to sodium citrate or GLDA (CAS 51981-21-6) where that is enough. For purely domestic use citrate is nearly always enough.

ChelatorHard waterPeroxide stabiliser

Sodium citrate Trisodium citrate · E331 · the green chelator

Na3C6H5O7 CAS 68-04-2 · dihydrate 6132-04-3
pH 1 %≈ 8.0
StrengthWeaker than EDTA
BiodegradableCompletely
Dose0.5–3 %
Price120–200 SEK/kg
Sold byBrewing supplier, pharmacy

You can make it yourself

If you already have citric acid and bicarbonate you do not need to buy sodium citrate. Dissolve citric acid in a little water and add bicarbonate in small portions until it stops fizzing — at that point all the acid is neutralised and you have citrate solution. It takes three moles of bicarbonate per mole of citric acid, which by weight comes to about 1.3 parts bicarbonate per part citric acid. Reading “three parts” as a weight is a common mistake and gives a heavily overdosed, alkaline solution.

C6H8O7 + 3 NaHCO3 → Na3C6H5O7 + 3 H2O + 3 CO2↑

Use it for

  • A chelator in everything you mix, as the environmentally sound first choice.
  • Water softener in the wash and the dishwasher.
  • A buffer when you want to hold a mixture steady around pH 6–8.
  • Dishwasher tablets in home-made form.
  • Emulsifying cheese, if you happen to end up there.
ChelatorFood-safeBiodegradableMake it yourself

Potassium soft soap Green soap · black soap · potassium salt of fatty acids

RCOO−K+ CAS 61789-30-8 among others
pH in use≈ 10
TypeAnionic
Dose5–20 ml/l
BiodegradableCompletely
Price40–80 SEK/l
Sold byGrocery

Old, cheap and still good

Soft soap is both a surfactant and a mild base in the same bottle, and it leaves a thin fatty film that genuinely nourishes untreated wood. The drawback is that it reacts with calcium in hard water and precipitates as lime soap — the grey film on the shower screen. A pinch of sodium citrate in the bucket cures that.

Use it for

  • Untreated and soap-scrubbed wooden floors — what it was made for.
  • General floor washing and rough cleaning.
  • Aphids and spider mites — 20 ml/l sprayed on the plant. The surfactant breaks down the insect's waxy layer. One of the most effective non-toxic garden measures there is.
  • Garden furniture and decking, as a pre-wash.
  • Hand-washing wool in dilute form.
  • Leak-testing gas lines — soap solution on the joint, and bubbles show the leak.
Wooden floorsGardenCheapLime soap risk

Xanthan gum E415 · thickener · polysaccharide

Polysaccharide CAS 11138-66-2
Dose0.2–1 %
pH-stable2 – 12
PropertyThixotropic
FormCream-white powder
Price200–400 SEK/kg
Sold byGrocery, health food shop

From spray to gel

A liquid on a vertical surface has perhaps ten seconds of contact time. The same liquid thickened to a gel has thirty minutes. That is the whole difference between something working and not, and it is why every effective commercial agent for ovens, rust and limescale is sold as a gel or a clinging foam. Xanthan is thixotropic as well: it thins under stirring so that it can be brushed on, and stiffens again as soon as it lies still.

Mixing it without lumps

Xanthan lumps immediately if you pour the powder into water. Two methods: sprinkle it very slowly into a strong vortex from a whisk or stick blender, or — better — first mix the powder with several times its volume of glycerol or alcohol into a smooth slurry, and then stir that into the water.

Use it for

  • Oven gel, limescale gel, rust gel, grout paste — anything that has to stay on a vertical surface.
  • Retrobright gel, see recipe 22.
  • Spot-treating stains where you do not want the agent to spread.
Limitation

Strong oxidants slowly break xanthan down. A peroxide gel with xanthan goes thinner after a day. For longer exposure or a stronger oxidant: use fumed silica.

ThickenerThixotropicCheap

Fumed silica Aerosil 200 · Cab-O-Sil · pyrogenic silica

SiO2 CAS 112945-52-5
Dose1–4 %
Chemical stabilityInert
DensityExtremely low
FormUltralight powder
Price300–500 SEK/kg
Sold byComposites supplier

The thickener oxidants cannot bite

Pure silicon dioxide in particles so small that they build a network in the liquid and make it thixotropic. Unlike xanthan it is chemically inert — it is not broken down by peroxide, caustic soda or acid, and can therefore be used in agents meant to work for days. It is the same material used to thicken epoxy into a filler.

Use it for

  • Peroxide gel for retrobright that has to sit for a whole day.
  • Caustic gel and acid gel where organic thickeners are broken down.
  • Epoxy filler — mix it into the resin until the consistency is like mayonnaise.
  • An anti-settling agent in your own suspensions.
Dust

The particles are respirable and the powder is so light that it hangs in the air for several minutes. Weigh it out wearing P3 respiratory protection or outdoors in still air, and never stir it at speed in an open vessel.

ThickenerInertEpoxyHazardous dust

Glycerol Glycerine · E422 · humectant

C3H8O3 CAS 56-81-5
RoleHumectant
Dose2–10 %
Freezing point18 °C (pure)
FormViscous
Price100–180 SEK/l
Sold byPharmacy, grocery

It keeps the mixture damp

An agent that dries stops working. Glycerol binds moisture from the air and keeps a gel willing to work for hours instead of minutes — particularly important outdoors, in sun, or in dry winter air. It is also what you mix the xanthan powder into so as to avoid lumps.

Use it for

  • A humectant in every gel that has to work for a long time.
  • Slurrying xanthan before mixing it into water.
  • Leather oil and rubber care, diluted.
  • Antifreeze in traps and water-based mixtures.
  • A plasticiser in your own soap and hand cream.
HumectantGel aidHarmless

Activated carbon Granules or powder · activated charcoal

C CAS 7440-44-0
Surface area500–1500 m²/g
ActionAdsorption
LifeUntil saturated
FormGranules / powder
Price150–300 SEK/kg
Sold byAquarium shop

Against smells that cannot be washed away

One gram of activated carbon has as much internal surface as half a football pitch. Volatile organic molecules stick there by physical adsorption. This is the right tool when a smell remains after the source itself has been removed — a chemical spill in a sofa, smoke, mould, solvent in a room. The difference from bicarbonate is large: bicarbonate only neutralises acidic smells, whereas the carbon takes practically anything organic.

Use it for

  • Smells in a room after a spill — open bowls of granules, changed after a week.
  • Furniture and textiles that smell — carbon in a cloth bag on top or inside, under cling film for a few days.
  • Fridge, shoes, car, wardrobe, bin area.
  • A filter in your own ventilation, drying cabinet or 3D printer enclosure.
  • Water treatment and aquariums.
  • Decolourising your own liquids and extracts.
It only works with time and proximity

The carbon has to sit close to the source and be left in peace. A bowl in the middle of the room does little; a bag shut in with the object under plastic does a great deal. Saturated carbon stops working entirely and can begin giving back — change it too often rather than too seldom.

OdourAdsorptionAfter a spill
08

Recipes

Thirty-three mixtures of the substances above. All quantities are by weight or volume for one litre of finished product unless stated otherwise. Weigh rather than measure by volume — household measures for powders are out by tens of per cent.

Before you mix anything
  • Mix in PP or HDPE. Never reuse a bottle that has held something else, and label everything with contents, strength and date — at once, not later.
  • Never mix in a closed container. Never mix more than you will use shortly, with the exception of the concentrates that are meant to be stored.
  • Always test on a hidden surface. Every time, even on a material you have treated before.
  • Read the mixing prohibitions in section 10 before you improvise.
What the words in the ingredient lists mean
  • Soda ash is the dry powder sodium carbonate. Not soda water, and not bicarbonate — which is admittedly called baking soda in the shops but is a different and considerably weaker salt, and cannot be substituted directly. Where a recipe says only “soda ash”, the anhydrous kind is meant; if you have washing soda crystals you weigh out 2.7 times as much, see Washing soda & soda ash.
  • A paste, cream or slurry means powder stirred with so little water that the consistency is like toothpaste: 3 parts powder to 1 part water, measured by volume, with the water added a little at a time. It has to stay on a vertical surface without running — if it runs, stir in more powder. Mix only as much as will be used at once; a paste that has dried on the surface stops working and should be dampened or replaced.
  • A gel is a finished solution thickened with xanthan gum or fumed silica, precisely so that it stays on vertical surfaces. The quantities are given in each recipe.
  • The percentage after a substance name — APG 50 %, hydrogen peroxide 12 %, phosphoric acid 85 %, ammonia solution 5 % — is the strength of the product you buy, not how much of it to use.
  • g/l is grams per litre of water. Ratios such as 1:1 and 3:1 are parts by volume unless stated otherwise — the same measure for both ingredients.

01 · All-purpose cleaner, concentrate

Everyday cleaning, kitchen, bathroom, painted surfaces. 1 l of concentrate makes 20 l ready to use.

All-purpose cleanergrocery Ajax allrent
IngredientQuantityRole
Water, lukewarm890 mlCarrier
Soda ash, anhydrous20 gAlkali, dissolves fat
Sodium citrate20 gChelator, softens the water
APG 50 %60 mlSurfactant
Isopropanol30 mlFaster drying, streak-free

How to do it

  1. Dissolve the soda ash and citrate in the water, stirring until it is clear.
  2. Stir the APG in carefully — slowly, or the whole batch foams over.
  3. Add the isopropanol last.
  4. Ready to use: 50 ml of concentrate per litre of water. The pH comes out around 10.

Not on aluminium, oiled or soap-scrubbed wood, marble and limestone. For those, swap the soda ash for another 10 g of sodium citrate — you get a neutral agent that is safe on everything.

02 · Descaling a coffee machine, kettle and espresso machine

It replaces every expensive descaler on the market. They contain the same thing.

Descalergrocery Häxan Antikalkcoffee machine Durgol
IngredientQuantityRole
Water1 lCarrier
Citric acid15 gDissolves and chelates the limescale

How to do it

  1. Fill the tank, start the programme and switch off when half the volume has gone through.
  2. Leave it 20 minutes so that the solution can work in the heater.
  3. Run the rest through.
  4. Rinse with three full tanks of clean water. This is the step people skip and then have sour coffee for a week.

Espresso machine: drop to 10 g/l and rinse four tanks — they have more narrow channels. Kettle: 20 g/l, bring to the boil, leave 20 min, rinse. Steam iron: 10 g/l, steam it through, rinse twice.

Do not use vinegar in machines with rubber seals. Acetic acid breaks down EPDM and silicone over time, and the smell stays for several brews.

03 · Limescale gel for shower screens, tiles and taps

The white film that will not come off with washing-up liquid. A gel, because vertical surfaces need contact time.

Limescale removergrocery Häxan Antikalk
IngredientQuantityRole
Water, hot860 mlCarrier
Citric acid100 gAcid + chelator
APG 50 %30 mlWets the surface
Xanthan gum5 gGelling agent

How to do it

  1. Dissolve the citric acid in the hot water.
  2. Mix the xanthan with the APG into a smooth slurry before it meets the water — otherwise it lumps.
  3. Stir the slurry into the acid solution while stirring vigorously. Let it swell for 15 minutes.
  4. Brush it on, leave 15–30 minutes, scrub lightly, rinse copiously.

Heavy limescale: swap the citric acid for 50 g of sulfamic acid. Never on marble, limestone, travertine or untreated concrete.

A phosphoric acid version — limescale and rust in one agent

The commercial limescale removers in the grocery aisle are usually exactly this mixture: phosphoric acid plus a surfactant, nothing else. The difference from the citric acid version is that the phosphoric acid also takes rust stains, which is why the bottles can promise both limescale and rust.

IngredientQuantityRole
Water870 mlCarrier
Phosphoric acid 85 %60 mlDissolves limescale and converts rust
APG 50 %30 mlSurfactant, takes the grease that sits on top of the limescale

Biltema's Kalk-fett-rostlösare (art. 363900) is the same idea in a bottle: under 5 % phosphoric acid and one fatty-alcohol ethoxylate, nothing else — about half the strength of the mix above, and still labelled corrosive, H314.

This gives about 9 % phosphoric acid. As a spray without thickener, as a gel with 5 g of xanthan. Let it work briefly — one to two minutes — and rinse copiously. Degrease first if the surface is greasy: an acid product cannot reach the limescale through a layer of skin oil, which is why the manufacturers themselves recommend an alkaline agent first.

Not on marble, natural stone, aluminium, galvanised, chrome, or etched and frosted glass.

04 · Maintaining the dishwasher and washing machine

Every three months. It takes limescale, detergent residues and smell in one go.

Machine cleanergrocery Finish maskinrengöring
  1. Dishwasher: 100 g of citric acid straight into the bottom of the empty machine. Longest programme, 60–70 °C.
  2. Washing machine: 100 g of citric acid in the drum. Empty cycle at 90 °C.
  3. Wipe the rubber seal around the door afterwards — that is where the smell actually sits.
  4. If the smell is strong: run an extra cycle with 100 g of sodium percarbonate at 60 °C. Run it separately, not at the same time as the citric acid.

Always leave the door ajar between washes. It does more against smell than any product.

05 · Grease-cutting kitchen spray

Worktops, tiles, hob fronts, the outside of the extractor. Ready to use, no dilution.

Kitchen degreasergrocery Mr Muscle kök
IngredientQuantityRole
Water925 mlCarrier
Soda ash, anhydrous15 gSaponifies the fat
Sodium citrate5 gChelator
APG 50 %25 mlSurfactant
Isopropanol30 mlDissolves the fat directly

Spray, leave 1–2 minutes, wipe off. Never let it dry on a glossy surface. Not on aluminium, natural stone or oiled wood.

If you want it stronger: add 10 ml of d-limonene. Shake before each use, since it is not completely stably emulsified.

06 · A bath for extractor filters and oven trays

The hardened fat comes off by itself. No scrubbing.

Degreasing bath
Check the material first

Most cooker hood filters are aluminium, and neat soda ash etches aluminium black in twenty minutes. There are two versions below — use the right one. If you are unsure: a magnet sticks to neither aluminium nor stainless, but aluminium is noticeably lighter and a dull light grey.

VersionMixture per litreTemp / time
Aluminium filters20 g metasilicate + 10 g soda ash + 5 ml APG60–70 °C · 20 min
Stainless or steel30 g soda ash + 5 ml APGas hot as the tap gives · 30 min

Soda ash here means anhydrous soda ash; if you have washing soda crystals you take 2.7 times the weight. See the explanations of terms before the recipes.

  1. Plug the sink, fill it with hot water, dissolve the powder.
  2. Put the filter in fully submerged. Turn it once.
  3. Rinse copiously and let it drain. Aluminium filters: rinse extra thoroughly and dry.

07 · Oven gel

The same thing as bought oven-cleaning sprays: caustic soda, surfactant and thickener.

Oven cleaninggrocery Mr Muscle ugn
IngredientQuantityRole
Water, cold890 mlCarrier
Sodium hydroxide50 gSaponifies burnt-on fat
APG 50 %30 mlSurfactant
Xanthan or fumed silica
the first figure is for the xanthan, the second for the silica		8 g / 25 gGelling agent

How to do it

  1. Pour the caustic soda into the water, never the other way round. In portions, while stirring. Fifty grams in a litre warms the solution by about 13 °C on its own — with twice the amount it is twice as much.
  2. Let it cool to room temperature before you go on.
  3. Stir in the APG, then the thickener.
  4. Apply in a cold oven with a brush. Leave it 30–60 minutes.
  5. Wipe it out with a damp cloth, rinse several times.
  6. Wipe over with 5 % citric acid solution to neutralise caustic residues, and then with clean water.
Protection and exceptions

Nitrile gloves and close-fitting goggles. Not on catalytic self-cleaning enamel (it is permanently destroyed), aluminium parts, the printed text on the oven glass, door seals or heating elements. Cover the ventilation holes.

A milder version: swap the caustic soda for 40 g of sodium metasilicate. Slower, but it works on most things and is considerably less dangerous to handle.

08 · Window cleaner

Streak-free because both the alkali and the solvent evaporate completely.

Window cleanergrocery Häxan fönsterputs
IngredientQuantityRole
Water, distilled for preference810 mlCarrier
Isopropanol150 mlDissolves fat, dries fast
Ammonia solution 5 %40 mlAn alkali that evaporates
APG 50 %2 mlWetting agent

The surfactant should be sparing. Too much gives exactly the streaks you are trying to avoid. Two millilitres in a litre is right.

Spray, pull off with a squeegee or wipe with microfibre. Never clean windows in direct sunlight — the agent dries before you have got the squeegee across.

Not on brass fittings (the ammonia causes stress corrosion), oiled wooden frames or anti-reflective coated screens.

09 · Drains: maintenance and blockages

The maintenance is cheap and harmless. The unblocking is not.

Drain openergrocery Plumbo, Mr Muscle, Häxancorrosive needs a permit in Sweden since 2025

Maintenance, once a month

  1. 100 g of anhydrous soda ash — sodium carbonate, the dry powder — straight into the drain. With washing soda crystals: 270 g.
  2. Two litres of boiling water after it.
  3. It keeps fat blockages away entirely without caustic soda.

A blockage

  1. Bail out standing water as best you can.
  2. 80 g of sodium hydroxide into the pipe, followed by 500 ml of warm, not boiling water.
  3. Leave it 30 minutes. Flush with plenty of warm water.
It is the ready-made bottle that has gone, not the caustic soda

Since 1 January 2025, drain openers — products sold for drain cleaning, with hydroxide at a corrosive concentration — have required a permit from the county administrative board for private individuals in Sweden. The caustic soda in this recipe is a raw material and is not covered; it is sold as before. But the accident statistics that led to the rule come from exactly this situation, and they do not care what the label on the tub says. The rules below therefore apply no less because you weighed the caustic soda out yourself.

Three absolute rules
  • Never caustic soda on top of an agent already standing in the drain, and least of all an acidic one. You cannot see what is down there.
  • Never a plunger or a drain snake while caustic soda is standing in the pipe — it splashes straight into your face.
  • Never in aluminium pipes or an aluminium trap. It gives off hydrogen and dissolves the pipe.

If the blockage is still there after two attempts it is mechanical: unscrew the trap, or use a drain rod. More chemistry does not help and only makes the job more dangerous for whoever opens the pipe.

10 · Oxygen bleaching of textiles

Wine, coffee, blood, grass, tomato, blackened banana, sweat, yellowed whites, discoloured tablecloths.

Stain removergrocery Vanish Oxi Action
IngredientQuantity per litreRole
Water, 60 °C1 lActivates the percarbonate
Sodium percarbonate20 g (whites: 30 g)Oxidant + alkali
Sodium citrate2 gChelator, in hard water
  1. Dissolve the powder in the hot water before the textile goes in.
  2. Soak 1–6 hours. Overnight is fine on whites.
  3. Wash as usual afterwards.

The temperature is decisive. In cold water almost nothing happens. If the solution falls below 40 °C the reaction stalls, so use a tub with a lid or top it up with hot water.

Never on wool, silk, leather or other protein fibres. Always test on coloured fabric.

11 · Enzyme soak

Blood, sweat, food, pet accidents and smell in the fibre — including on wool and silk, where oxygen bleach is out of the question.

Pre-wash and soaking
IngredientQuantity per litreRole
Water, 40 °C1 lThe enzymes' working temperature
Enzyme detergent or protease powder5 gCuts the dirt apart
Sodium citrate2 gChelator, in hard water
APG 50 %5 mlWets the fibre

How to do it

  1. First rinse fresh blood out in cold water. Hot water coagulates the protein and makes the stain permanent — this step decides the outcome more often than the enzyme itself.
  2. Mix in water at 40 degrees. No hotter: above 60 °C the enzyme is dead.
  3. Soak 1 hour to overnight. Under 20 minutes almost nothing happens.
  4. Wash as usual afterwards, at no more than 40 °C if the garment is wool or silk.

Do not combine it with the oxygen bleach. Percarbonate breaks the enzyme down. If the garment needs both: do the enzyme soak first, rinse, and do the oxygen bleaching as a separate second step — and only if the material can take it.

It does not keep in advance. Make the bath up when you are going to use it; enzymes in dilute solution lose activity within a day.

12 · Your own PBW — universal cleaner for vessels and equipment

The brewing industry's standard agent. It dissolves burnt-on organic matter, yeast residues, coffee deposits, protein residues and blood without scrubbing.

Brewery cleanerbrewing supplier PBW
IngredientProportionRole
Sodium percarbonate60 %Oxidant + alkali
Sodium metasilicate40 %Dissolves fat + protects light alloys

The proportions are per cent by weight: 60 g of percarbonate and 40 g of metasilicate give 100 g of powder. Mix dry in a sealed tub. Dose 10–20 g per litre of water at 50–60 °C. Soak 20–60 minutes, rinse thoroughly.

Thanks to the silicate it is milder on aluminium than neat soda ash, but even so do not leave aluminium parts in the bath overnight. Not on wool, leather or soft plastic that has gone brittle.

13 · Decking, step 1: algae, moss and dirt

Done in the spring. Step 2 follows only if the wood is to be lightened.

Decking cleanergrocery decking washtrade supplier Hagmans Tralltvätt
IngredientQuantity per litreRole
Water, hot1 lCarrier
Sodium percarbonate30 gOxidises biological growth
APG 50 %10 mlWets the wood
  1. Wet the whole area with clean water first — dry wood takes the agent up unevenly and you get streaks.
  2. Apply, keep it damp for 15–20 minutes, top it up if it dries.
  3. Brush with a stiff brush along the grain.
  4. Rinse copiously.

Water the planting around the deck both before and after — that dilutes what runs off. Percarbonate is very much gentler on wood than bleach, which raises the fibre and leaves the surface furry.

14 · Decking, step 2: lightening greyed wood

It restores silver-grey or blackened wood to nearly new. Before oiling.

Wood lightenersold as oxalic acid, not as a finished product
IngredientQuantity per litreRole
Water, hot1 lCarrier
Oxalic acid60 gDissolves iron stains, bleaches lignin
  1. Gloves, close-fitting goggles, long sleeves. Weigh the powder out of doors.
  2. Cover galvanised and zinc-plated fittings, screw heads and light alloy fittings.
  3. Wet the wood, apply, brush, leave 20 minutes.
  4. Rinse very copiously. Residues interfere with the adhesion of the oil and can migrate to the surface later.
  5. Let it dry for at least two days before oiling.

Neutralise leftover solution with soda ash or lime before pouring it away. Do not pour concentrated oxalic acid solution onto a lawn or a flower bed.

15 · Rust conversion gel before painting

Chassis, frames, tools, garden furniture, sheet metal. It gives a black phosphate layer the paint keys to.

Rust converterpaint shop Hagmans Carosolcar accessory Biltema Rostätare — tannin, different chemistry
IngredientQuantityRole
Water780 mlCarrier
Phosphoric acid 85 %200 mlConverts rust to iron phosphate
APG 50 %10 mlWets oily metal
Xanthan6 gStays on a vertical surface
  1. Acid into water, never the other way round. This gives about 25 % working strength.
  2. Brush loose flakes off with a wire brush first.
  3. Brush it on, keep it damp for 15–30 minutes. The surface turns grey-black when the reaction is finished.
  4. Wipe off the excess, rinse lightly with water, dry completely.
  5. Prime the same day. The phosphate layer is hygroscopic and starts rusting again within a day.

Not on zinc-plated or galvanised — you eat up the corrosion protection. Not on aluminium, chrome or natural stone.

16 · Electrolytic rust removal

Threads, cavities, tools of complex shape. It takes rust off where no brush can reach, without attacking the sound metal.

Rust removal
PartChoiceNote
VesselPlastic bucket, PP or HDPENever metal
Electrolyte20 g anhydrous soda ash per litreA conductor only, not consumed
Cathode (−)The object to be cleanedGood contact above the water line
Anode (+)Reinforcing bar or carbon steelSacrificial, replaced
Current5–12 V DC, 2–10 ABattery charger or bench supply
Two things that have to be right
  • Never use stainless steel as the anode. The chromium in the alloy is oxidised to hexavalent chromium, which is carcinogenic and turns the whole bath into hazardous waste. Ordinary reinforcing bar is the right choice.
  • Hydrogen and oxygen form at the electrodes. That is an explosive mixture. Work outdoors or under good ventilation, no flame and no spark nearby, and never cover the vessel over.
  1. Place the anode so that it “sees” the rusty surface — the current takes the straightest route and shadowed areas are not cleaned.
  2. Run it 2–24 hours depending on size. The water goes orange-brown and foamy.
  3. Take it out, brush off the black layer, rinse.
  4. Oil it immediately. A freshly cleaned surface flash-rusts within minutes.

17 · Rust stains in textiles, concrete and porcelain

Stains from flowerpots, furniture legs, reinforcement, nails in wood and forgotten paperclips.

Rust stain remover
LevelMixture per litreTime
Mild — always try this first50 g ascorbic acid30 min
Strong50 g oxalic acid15–30 min
Concrete, vertical50 g oxalic acid + 5 g xanthan1–2 h

Apply, keep damp, rinse copiously. On textiles: rinse until the rinse water runs clear and then wash the garment normally.

Never on marble, limestone or terrazzo. Test coloured textiles on a hidden seam. Gloves with oxalic acid.

18 · Silver polishing without abrasion

Electrochemistry instead of silver polish. It wears no metal away at all.

Silver polishinggrocery Häxan silverputs
IngredientQuantityRole
Aluminium foilthe bottom coveredReductant, sacrificial
Water, 70 °C1 lElectrolyte
Bicarbonate of soda15 gElectrolyte, mild base
Table salt5 gConductivity
  1. Line the bottom of a glass or plastic bowl with foil, shiny side up.
  2. Pour on the hot water with the bicarbonate and salt.
  3. Put the silver in so that it touches the foil — the whole reaction depends on electrical contact.
  4. 2–10 minutes. The blackening disappears while you watch. Rinse and dry.
3 Ag2S + 2 Al → 6 Ag + Al2S3

The silver sulfide is reduced back to metallic silver — no silver is lost, unlike polishing with an abrasive.

Not on silver with a deliberately oxidised pattern (the patina goes and does not come back), glued-in stones, pearls, or an antique whose patina is part of its value.

19 · Passivating stainless steel

After welding, grinding, drilling or bending. It builds up the chromium oxide layer that makes the steel stainless in the first place.

Passivating
IngredientQuantityRole
Water900 mlCarrier
Citric acid100 gDissolves free iron, leaves the chromium alone
  1. Degrease first. Passivating an oily surface does nothing at all. Soda ash or IPA.
  2. 60 °C for 30 minutes, or room temperature for 60–90 minutes. Dip it or apply as a gel.
  3. Rinse with distilled water if you have it — the chlorides in tap water work against the purpose.
  4. Dry completely. The oxide layer then finishes growing by itself in air over a day.

It works because the citric acid dissolves free iron on the surface — grinding dust, tool deposits, weld tint — but leaves the chromium untouched. That is why citric acid has replaced nitric acid as the industry standard. Never use hydrochloric acid on stainless: the chlorides cause pitting that is invisible until the hole goes right through.

20 · Washing a circuit board after soldering

Flux residues, fingerprints, dust. Done right, the board looks factory-new.

Flux removal
LevelMediumMethod
OrdinaryIPA 99.5 %Stiff brush, wipe with a lint-free cloth
Stubborn ionic residuesIPA 90 % + 10 % deionised waterBrush, then rinse in clean IPA
Heavily soiledHot water + 5 ml/l APGRinse in deionised water, then IPA
  1. Brush in one direction, collecting the residues instead of moving them around.
  2. Blow dry with compressed air.
  3. Let it dry at least 30 minutes, preferably in a 50 °C oven or drying cabinet, before any voltage is applied.
Avoid

Acetone — it dissolves component markings, plastic housings, relay cases and connectors. An ultrasonic bath on boards with crystal oscillators, MEMS sensors, open relays, trimmer potentiometers or electrolytic capacitors with a rubber seal. Methylated spirits, which leaves residues from the denaturant.

That plain water works surprises many people. Industrial assembly washes boards in deionised water with a surfactant and dries them in an oven, and it is entirely unproblematic — as long as all the water really is gone before the board gets power. The water need not come from a chemical supplier: demineralised battery water from a car accessory shop is ion-exchanged and sold in five- and ten-litre canisters, which is plenty for rinsing.

21 · Removing adhesive

Labels, price stickers, duct tape, double-sided tape, old masking tape.

Adhesive removercar care Label Off
  1. The standard method: petroleum spirit on a rag. Keep the surface wet for 30 seconds so that the solvent has time to work into the adhesive, then rub. Repeat rather than rub harder.
  2. A vertical surface or a big blob of adhesive: make a paste of petroleum spirit and fumed silica so that it stays put. Cover with cling film, 10 minutes.
  3. Plastic that cannot take petroleum spirit (polystyrene, some ABS): d-limonene, or cooking oil followed by all-purpose cleaner.
  4. A paper label: soak it with warm water and a little vinegar first, scrape the paper off, then take the adhesive with petroleum spirit.
  5. Always finish with all-purpose cleaner — solvents leave a greasy film that attracts dust.

Heat helps more than most people think. A heat gun on a low setting or a hairdryer makes the adhesive soft enough to roll off mechanically before you use any solvent at all.

22 · Retrobright gel

De-yellowing ABS plastic on old computer equipment, consoles and keyboards.

De-yellowing plastice.g. — not sold ready-made
IngredientQuantityRole
Hydrogen peroxide 12 %
hairdressing wholesaler, “40 volume” developer		500 mlOxidant
Fumed silica15 gA gelling agent the peroxide does not break down
APG 50 %2 mlEven wetting, fewer streaks
EDTA or sodium citrate1 gStabilises the peroxide

How to do it

  1. Take it apart and clean the plastic completely first. Grease and dirt give patches in the result.
  2. Apply the gel evenly with a brush. Uneven application gives permanent marbling — this is the commonest way to ruin a part.
  3. Wrap it in cling film so that the gel does not dry.
  4. UV lamp or direct sun. 4–12 hours. Turn and rotate it every hour.
  5. Check often. Rinse it off when the colour is even, and dry.
What you should know before you start
  • The effect is not permanent. The yellowing comes back, often within one to three years.
  • The treatment makes the ABS more brittle. Thin screw posts and clips can snap afterwards.
  • It only works on yellowing from degraded brominated flame retardants. Discolouration from smoke, sun or pigment is unaffected.
  • 12 % peroxide gives white chemical blisters on skin within seconds. Gloves and goggles.

A percarbonate version if you cannot get hold of 12 % peroxide: 100 g of sodium percarbonate in 500 ml of water at 40 degrees. More than that will not dissolve — you are already close to saturation. It gives about 5 % peroxide equivalent, so barely half the strength, plus an alkaline pH that if anything speeds the reaction up. Reckon on about twice the time, and make it up fresh every day — the solution loses strength within hours.

23 · Gentle wheel and light alloy wash

pH-neutral. Safe on clear coat, polished aluminium and anodised surfaces.

Wheel cleanercar care Sonax, Turtle Wax
IngredientQuantityRole
Water930 mlCarrier
APG 50 %40 mlSurfactant
Sodium citrate10 gChelator, lifts brake dust
Isopropanol20 mlDissolves tar and grease

Spray it on a cold wheel, leave 3–5 minutes, brush, hose off. Never on a hot wheel and never in sunshine — the agent dries on and leaves marks.

What you should never use on light alloys

Strongly alkaline “wheel cleaners” etch polished and unpainted aluminium permanently matt. Products with fluorides or hydrogen fluoride should never be brought home at all. Hydrogen fluoride causes burns that do not hurt for several hours, and the fluoride ion goes on binding the body's calcium long after the skin looks undamaged — the injury is systemic, not merely local. If you see them in a consumer pack, put it back. If you need to remove embedded iron particles, the answer is not a stronger wheel cleaner but a different substance, see below.

Fallout rust is what the recipe leaves — thioglycolate takes it

The orange-brown specks on light paint are iron particles from brakes and railway lines that have burned into the paint rather than sitting as dirt on it. No surfactant touches them, and acid only gets them by attacking everything else on the way. What works is thioglycolate: the thiolate ion binds the iron into a water-soluble complex that turns purple-red, and the colour shift is the receipt that it is working — once the surface stops going purple it is clean. Being neither acidic nor alkaline it leaves clear coat, anodising, wax and ceramic coatings alone, and that is the whole reason to pick it over acid.

The substance is not sold as a raw material, only as a finished fallout remover. Biltema's Super Detox (art. 361931) is one of the cheaper ones and holds, according to its safety data sheet, 10–30 % sodium mercaptoacetate — that is sodium thioglycolate — plus a per cent or so of surfactant: the same active substance the car-care brands sell as “iron remover” at several times the price.

How it is used, and why gloves

Cold surface in the shade, 3–5 minutes, never let it dry on, rinse generously — above all out of gaps and wheel spokes, where the residue otherwise stays behind and keeps working. Thioglycolate is classified as a skin sensitiser (H317) and harmful if swallowed (H302); a thioglycolate allergy lasts for life, and it is the same substance behind occupational eczema among hairdressers. Nitrile gloves, and no spraying in a still garage — the sulphur smell is the least of it. Do not combine it with an acidic wheel cleaner: the point of thioglycolate is precisely to avoid the acid, and a low pH also makes the stench worse.

24 · Mould in grouting and silicone

Black spots in the shower grout. Chemistry takes the colour — the damp is the real problem.

Mould washpaint shop Beckers Alg & Mögeltvätt
VersionMixtureTime
Oxygen-based6 % hydrogen peroxide + 5 g/l xanthan2–6 h under film
A pasteSodium percarbonate + water 1:1 by volume, as a thick slurry2–4 h
  1. Apply, cover with cling film so that it does not dry.
  2. Rinse, ventilate, wipe the grout dry.
  3. If the blackening is still there, the mycelium has grown into the silicone. No chemistry helps then — cut it out and re-seal.

Bleach is more effective on this particular thing, but it bleaches grout and silicone, must not be combined with anything else in the bathroom, and does not deal with what has grown in either. Sort out the ventilation and wipe the shower screen down after every shower, and it will not come back.

25 · Clearing a smell after a chemical spill in furniture or textiles

When the source has been removed but the smell is still in the padding or the weave.

Odour removal
  1. Mechanically first. Suck and blot up everything you can. The chemistry should not have to work against a remaining pool.
  2. If the substance is an ester — which covers many solvents, plasticisers and most “chemically sweet” smells — it is broken by alkaline hydrolysis. Mix 30 g of anhydrous soda ash and 5 ml of APG per litre of lukewarm water. Work it into the textile, leave 20–30 minutes, extract it, rinse with clean water, extract again.
  3. Dry completely. A fan and a dehumidifier for preference. Moisture left in the padding gives a mouldy smell on top of the original one.
  4. Activated carbon. Granules in cloth bags, tight up against or inside the furniture, the whole thing covered with a blanket or a tarpaulin. 3–14 days. Change the carbon once along the way.
  5. If it persists: professional ozone or hydroxyl treatment. Ozone must not be used in a room anyone is in.

Test the alkali step somewhere hidden first. Soda ash can affect colour and some fibres, and water-based treatment of certain upholstery fabrics leaves marks that are harder to remove than the smell.

26 · Cleaning up a leaked battery

Three entirely different chemistries with three entirely different responses. Choosing wrong makes it worse.

Battery clean-upe.g. — not sold ready-made
Battery typeLeaksNeutralised with
Alkaline (AA, AAA, 9V)Potassium hydroxide — alkaline10 % citric acid or vinegar
Lead-acid (car, UPS)Sulphuric acid — acidicBicarbonate, generously
Lithium-ionOrganic electrolyte + LiPF6Dry absorbent, see below

Alkaline leakage in a battery compartment

  1. Gloves. The white powder is corrosive and stays there for years.
  2. A cotton bud dampened with 10 % citric acid solution. Work at it until the fizzing stops.
  3. Dry, rinse with IPA, dry completely.
  4. If the contact spring has lost metal: carefully grind back to clean surface, or solder on a new one.
Lithium cells

Do not use water. The electrolyte's LiPF6 reacts with moisture and forms hydrofluoric acid, which causes injuries that are not felt until hours later. Ventilate, wear nitrile gloves, mop up with dry absorbent material and sprinkle bicarbonate dry onto the substrate. The cell goes for recycling — a damaged or swollen lithium cell should never be stored indoors.

27 · Workshop hand wash

Oil, grease, soot, pitch, ink. Abrasive plus solvent plus humectant.

Workshop soaptrade supplier Swarfega
IngredientQuantityRole
Water220 mlCarrier
APG 50 %100 mlSurfactant
D-limonene30 mlDissolves oil, pitch and ink
Glycerol50 mlCounteracts dried-out hands
Fine silica flour or cornflour
silica flour = ground quartz, sold at builders' merchants and pottery suppliers		100 gMechanical scrub

Mix it in a tub with a wide lid. Take a blob on dry hands, rub it in thoroughly, then add a little water and go on rubbing before you rinse. Wetting your hands first is the commonest mistake — the solvent then never reaches the grease.

Shake or stir before each use; the abrasive settles.

Silica flour bites better but raises quartz dust: pour the powder inside the liquid, not the other way round, and do not breathe the dry powder in. Cornflour is entirely harmless and almost as effective.

28 · Oil and grease in concrete

Garage floors, drives, workshop concrete, the oil patch under the car. It works on brick, natural stone and unglazed tile too.

Concrete degreasingcar accessory Biltema Oljesanering
Why the stain comes back

Concrete is porous. The oil is not on the floor but several millimetres down in the pore system. Scrub the surface and you take away the film, and a week later the oil has migrated back up. Everything that works on the surface — degreaser, pressure washing, scouring powder — fails for the same reason. The answer is to draw the oil out rather than wash it off.

A fresh spill, within a day

  1. Sprinkle cat litter, vermiculite or sawdust on at once and generously.
  2. Let it soak for an hour. Tread on it lightly so that the grains reach down into the surface.
  3. Sweep it up and sprinkle fresh on if it still goes dark.
  4. Do not hose it. Water drives the oil deeper and makes the rest of the job harder.

Ingrained: the poultice, the method that actually removes it

A paste of solvent and absorbent that is allowed to dry slowly. As the solvent evaporates it travels upwards and takes the oil with it out into the powder.

IngredientQuantityRole
White spiritabout 200 mlDissolves the oil, evaporates slowly
Absorbent
diatomaceous earth, fumed silica, talc or ground cat litter		to consistencyTakes it up and holds on to it
  1. Stir to a paste like thick yoghurt. It must not run.
  2. Spread it on half a centimetre thick, a couple of centimetres beyond the edge of the stain.
  3. Cover with cling film and tape it down all round. Leave it a day so that the solvent has time to work down into the pores.
  4. Take the plastic off. Let it dry completely, one to two days. This is when the oil comes up — the evaporation is the whole driving force, so do not hurry it along with heat or a fan.
  5. Sweep up the dry paste and hand it in as hazardous waste.
  6. Repeat. Old engine oil often takes three rounds, and each round comes out lighter.

White spirit rather than petroleum spirit here in particular: the slow evaporation is the point. Petroleum spirit works but dries before it has got down into the pores. D-limonene works too and smells better, but costs appreciably more over this sort of area.

A shallow, fresh film of oil

IngredientQuantity per litreRole
Water, hot1 lCarrier
Sodium metasilicate20 gSaponifies and lifts the grease
Soda ash, anhydrous10 gAlkalinity
APG 50 %10 mlWets the concrete

Pour it on, scrubbing brush, leave 20 minutes without letting it dry, rinse. Enough for a spill that has sat for months, but not for years. If the stain has been there a season: go straight to the poultice.

What is actually in a bottle of ready-made concrete degreaser

Biltema's Oljesanering (art. 36-3930) holds, according to its safety data sheet, alkyl polyglucoside C8-10 at 1–2 % and C10 alcohol ethoxylate at 1–3 %, phenoxyethanol as a preservative, and otherwise water. The alkyl polyglucoside is the same substance as the one on the APG card — the same CAS number, 68515-73-1. The surfactant this document is built on is the one on the shelf, which is a good sign for both.

The difference lies elsewhere. The bottle has more surfactant than the mix above but a pH of about 7. The mix above has less surfactant and a pH around 12, because the metasilicate and the soda do what the surfactant cannot: saponify the fat. A surfactant lifts and emulsifies what has already come loose — it breaks no ester bonds.

That makes the ready-made product the right tool for a fresh film of oil on a sealed surface, and the wrong tool for this recipe's problem. It works on the surface, which is precisely what the paragraph at the top says does not work on oil that has already travelled down into the pore system. No product on that shelf does — which is why the poultice exists.

Three things that make it worse
  • A pressure washer as the first move. The pressure drives the oil deeper into the pore system and spreads it over a larger area. Use it after the chemistry, never before.
  • Acid. It does nothing at all against oil — it dissolves the lime in the concrete, not the grease. The result is a roughened, more absorbent surface that takes up even more next time.
  • Solvent down the drain. Never rinse the poultice away. See section 12.
Afterwards

A clean concrete surface soaks up just as willingly next time. If you would rather not do it again: impregnate it with a silane- or siloxane-based concrete sealer once the surface is completely dry. The next spill then stays on the surface and wipes off with a cloth.

29 · Disinfectant solution of known strength

Surfaces after a drain flood, infection in the household, chopping boards after chicken, equipment that has to be clean and not merely look clean.

Surface disinfection
IngredientQuantityRole
Water, cold1 lCarrier
Calcium hypochlorite 70 %3 g0.2 % available chlorine

How to do it

  1. Clean first. Chlorine is used up by dirt before it has time to disinfect — a dirty surface exhausts the solution instead of getting clean.
  2. Dissolve the granules in cold water. The solution goes cloudy from the calcium; that is normal.
  3. Apply and leave it 15 minutes. Any less is not disinfection.
  4. Do not rinse afterwards — except on stainless, which must be rinsed so that it does not corrode.
  5. Mix fresh every time. The solution loses strength within a day.

A weaker version: 0.75 g/l gives 0.05 %, which is enough for laundry and for surfaces that only need a final disinfection. Stronger: 15 g/l gives 1 %, for spill buckets and heavily contaminated things. The strengths and the contact time follow MSF's table for chlorine solutions.

Not for drinking water

The Swedish Food Agency's limit is 0.5 mg of free chlorine per litre at the tap — four thousand times weaker than this solution, and not something to be dosed by eye. If you need to disinfect a well, ask your local environmental health office.

Never mix with

Acid, chlorine tablets or ammonia. Chlorine tablets and these granules are both “chlorine” but chemically opposite — together they give fire. See Mixtures.

30 · Heavy descaling and pickling with a dry acid

Limescale that citric acid will not bite: water heaters, heating coils, a toilet with a hard deposit. And pickling steel before painting.

Heavy-duty descaler
IngredientQuantityRole
Water1 lCarrier
Sodium bisulfate50 gThe acid, gives pH ≈ 1.2
APG 50 %2 mlWets a vertical surface, optional

How to do it

  1. Stir the powder into the water, never the other way round. The solution gets warm.
  2. Leave it 30 minutes to a few hours. The limescale stops fizzing when it is gone.
  3. Rinse copiously. On steel: dry it at once, or the rust flies on within an hour.
  4. Neutralise the residues with bicarbonate before they go down the drain.

Toilet: empty the water out with the brush, pour the powder on dry and mist it lightly — it works where a solution would simply run away. Pickling: 100 g/l and ten minutes gives a matt, clean surface that takes paint.

Avoid on

Aluminium, galvanised, natural stone and concrete. The sulfate ion attacks cement more slowly than it appears to — the damage shows up after a season.

31 · Copper and brass without metal polish

Darkened candlesticks, copper pan bases, door handles, brass fittings and verdigrised ornaments.

Metal polishgrocery Häxan metallputs
IngredientQuantityRole
Water1 lCarrier
Citric acid100 gDissolves the oxide
Table salt30 gThe chloride speeds the attack up

How to do it

  1. Check first whether the object is lacquered. Most of today's brass fittings are. The acid then does nothing at all to the metal and everything to the lacquer. Try it on a hidden edge: if the surface goes dull it is lacquered, and then it is the lacquer that has to come off first.
  2. Dip it, brush it on, or lay a soaked cloth on the surface. It takes one to five minutes, and you can watch the change happen.
  3. Rinse copiously and dry completely, at once. Freshly polished copper is bright and naked and starts darkening again within hours in damp air.
  4. If you want to keep the shine: thin oil or wax. Otherwise the patina comes back, which for most objects is entirely as it should be.
Why not the same trick as the silver

Recipe 18 polishes silver without sacrificing a single atom, because silver sulfide can be reduced back to metallic silver. Copper's tarnish is an oxide, and it cannot be reversed the same way — it has to be dissolved. So a little copper goes every time, and so the recipe is something to reach for when it is needed rather than every month.

Leave alone

Green verdigris on copper roofs, downpipes and outdoor objects is a protective layer that has taken decades to form. Gilded or thinly plated surfaces cannot take the treatment at all.

32 · Silicone remover for old sealant

Cured sealant in the shower, around the sink and in window rebates. It does not dissolve the silicone — it swells it, until the bead lets go of the surface.

Silicone removalbuilders' merchant Biltema Silikonborttagning
IngredientAmountRole
D-limonene180 mlSwells the silicone network
APG 50 %10 mlLets the residue rinse off with water
Fumed silica
for the gel version only		8 gStays put in a vertical joint

How to do it

  1. Mechanically first, always. Cut the bead loose with a sealant knife or a razor blade and pull it away in one piece. The chemistry is only there for the thin skin left behind in the joint — pouring solvent over a whole bead is waiting hours for nothing.
  2. Brush the mixture over what remains, cover with cling film so it cannot evaporate, and leave it 1–2 hours. Swelling is slow and cannot be hurried with heat.
  3. Rub the softened residue away with a wooden or plastic scraper. If something stays put, repeat rather than letting the first round dry on.
  4. Wash the joint with all-purpose cleaner and rinse. The surfactant in the mix is there for this step — without it the terpene stays behind as a greasy film.
Why nothing dissolves cured silicone

The silicone in a joint is a cross-linked network of polydimethylsiloxane. The chains are held together by chemical bonds, and a cross-linked network cannot by definition be dissolved — only swollen. D-limonene works because its solubility parameter sits close to the silicone's: the terpene forces its way in between the chains, the network swells, and its grip on the surface fails. The mass turns soft and jelly-like rather than liquid, and that is what success looks like.

So every “silicone remover” is really a silicone sweller, and that is why the mechanical work comes first and the chemistry last.

What else it attacks

D-limonene takes polystyrene and some ABS, softens rubber seals, and dissolves asphalt, tar and most paints. Test on a hidden spot before brushing it along the edge of a plastic bath. The terpene is also a skin sensitiser (H317), and old, air-exposed limonene is worse than fresh — nitrile gloves and ventilation, and keep the bottle closed.

Compared with the bottle

The finished product is the same two components. Biltema's Silikonborttagning (art. 364824) holds, according to its safety data sheet, over 75 % d-limonene and 2.5–5 % C9-11 alcohol ethoxylate — a non-ionic surfactant in exactly the role APG plays here. The recipe above is not an imitation of it but the same mixture, using the surfactant this document already keeps.

And for once it runs the other way: the bottle is probably cheaper. Neat d-limonene costs 250–450 SEK a litre by the buying table above, and a ready-made half litre normally comes in under that. Mix your own if you already keep the raw material, or if you want the gel version — the shop product is thin and runs straight out of a vertical joint.

This does not remove silicone contamination

Getting a bead out and getting a surface paintable again are two different problems. Silicone oil migrates and leaves an invisible low-energy film that makes paint crawl into fisheyes, and that film stays after the bead is gone. See Limmet, section 7 — the short version is that the surface cannot be fully rescued.

33 · Bubble mix without dye or cationic polymer

A bubble solution that does not ruin the laundry. Bought mix contains a cationic polymer that precipitates in the washing machine — see the register. This one has none, and no dye either.

Bubble solutiontoy shop Gazillion, Fubbles
IngredientQuantityRole
Water, deionised1 lCarrier
APG 50 %20 mlSurfactant, about 1 % active content
Glycerol100 mlSlows the evaporation
Sodium citrate2 gChelator — only if you are using tap water

How to do it

  1. Dissolve the citrate in the water first, if you are using tap water. With deionised or distilled water you can skip it.
  2. Stir in the glycerol.
  3. Add the APG last and stir slowly. Stir hard and the whole batch foams over, and then you have to wait it out.
  4. Let it stand a few hours before you use it. A fresh mixture gives poorer bubbles than one that has rested.
Less surfactant, not more

The obvious move when the bubbles will not hold together is to pour in more washing-up liquid. It is the wrong way. A controlled study of bubble recipes found that too high a surfactant concentration worsens both how easily the bubble forms and how long it lives — around 4 per cent by volume of ordinary washing-up liquid was the optimum, which is under one per cent active surfactant. The film needs enough surfactant for the Marangoni stress to hold it, and no more.

If you want metre-wide bubbles

Add 1 g of guar gum per litre. The same study settled on 0.1 % guar, and the mechanism is elongational viscosity: long polymer chains let the film be drawn out without breaking, which is exactly what happens as a large bubble leaves the ring. Slurry the powder in the glycerol first, as with xanthan, or it lumps. Guar is not interchangeable with xanthan here — attempts to substitute xanthan in bubble recipes have given poorer results, so buy guar if you want this.

The chelator does nothing in the lab and something in the kitchen

The study above found no effect from citric acid or pH adjustment. It was run on ultrapure water. Your tap water contains calcium, and calcium consumes the surfactant as lime soap — the same thing first principle 4 is about. The citrate is there for the water, not for the bubble, and is not needed at all if you pour deionised water instead.

09

Material table

Look the material up before you choose an agent. The table saves more than it looks as though it does — most failures in home chemistry are damage to the material, not a failure to clean.

Key

✓ normally safe  ·  ! brief contact, rinse at once, test somewhere hidden first  ·  ✗ avoid — risk of lasting damage

The table assumes working strength as in the recipes, room temperature and rinsing afterwards. A higher concentration, a higher temperature or a longer contact time moves everything one step to the left.

Material against agent
Material Weak acid
citric, acetic		 Strong acid
phosphoric, oxalic, sulfamic, HCl		 Soda ash
carbonate		 Caustic soda
NaOH		 Ammonia Peroxide
percarbonate		 IPA
ethanol		 Acetone Petroleum spirit
white spirit
Stainless steel✓!✓✓✓✓✓✓✓
Carbon steel, iron!!✓✓✓!✓✓✓
Aluminium, unpainted!✗✗✗✗✗✓✓✓
Aluminium, anodised!✗✗✗✗!✓✓✓
Zinc-plated, galvanised✗✗✗✗!!✓✓✓
Copper!!✓!✗!✓✓✓
Brass, bronze!!✓!✗!✓✓✓
Silver!✗✓!!✗✓✓✓
Chrome✓✗✓!✓✓✓!✓
Car paint, clear coat!✗!✗✗!!✗✓
Enamel (bath, white goods)✓!✓!✓✓✓!✓
Glass✓✓✓!✓✓✓✓✓
Marble, limestone✗✗!!!✓✓!✓
Granite, polished!✗!✗!✓✓!✓
Concrete, tile grout✗✗✓✓✓✓✓✓✓
Wood, untreated✓!✓!!✓✓✓✓
Wood, lacquered or oiled!✗✗✗✗!!✗!
ABS✓✓✓✓✓!✓✗✓
Polycarbonate✓!✗✗✗✓✗✗!
Acrylic, PMMA✓!!✗!✓✗✗!
PP and HDPE✓✓✓✓✓✓✓✓✓
PVC✓✓✓✓!✓✓✗!
Rubber, EPDM!✗!✗!!!✗✗
Silicone✓!✓!✓✓✓!!
Cotton, linen✓!✓!✓✓✓✓✓
Wool, silk!✗✗✗✗✗!!!
Leather!✗✗✗✗✗✗✗✗

Four patterns in the table

  • Aluminium and zinc are the alkali's enemies. They are amphoteric — attacked by acid and by base alike. If anything of light alloy is involved: stay between pH 5 and 9, or use sodium metasilicate as an inhibitor.
  • Everything containing lime dies of acid. Marble, limestone, travertine, terrazzo, concrete, cement grout and lime plaster are the same chemistry as the limescale you are trying to dissolve. The acid cannot tell them apart.
  • Protein cannot take alkali or oxidants. Wool, silk, feather and leather are rows of exactly the bonds that caustic soda and peroxide break. Here the pH route cannot be taken at all — enzymes are the tool that remains, because they work at neutral pH and attack the dirt instead of the material.
  • PP and HDPE take everything. That is why every chemical drum is made of them, and why you should always mix in a PP vessel. Look for recycling code 2 or 5.
10

Mixtures

Which combinations produce something useful, and which must never arise — neither deliberately nor by two agents being used one after the other on the same surface.

Can I mix these?

Choose two substances. The answer comes from the tables below, so that you do not have to find the row yourself — which is the whole point, since somebody standing with two bottles in their hands rarely begins by reading a table.

Common mistakes
Never — without exception

Almost every serious accident in home chemistry involves bleach, and almost all of them happen by mistake: two agents one after the other in the same toilet, the same bucket or the same drain. If you are going to remember only one thing from this document, it is that bleach must not meet anything else.

Dangerous combinations
CombinationGivesConsequence
Chlorine tablets (TCCA) + shock chlorine (calcium hypochlorite)NCl3Fire or explosion. Both are called “chlorine” and stand in the same store — which is exactly why the accident happens. They are shipped separately for the same reason.
Dry chlorine + pH minus (sodium bisulfate, in the same store)Cl2Chlorine gas. Two powders do not have to be poured together: a spill and moisture in the air are enough.
Calcium hypochlorite + oil, rag or leavesFireA strong oxidant against organic material. Granules in an oily rag can self-ignite without a spark.
TCCA + urea, ammonium salt or fertiliserNCl3Nitrogen trichloride. The same shock-sensitive compound that bleach and sulfamic acid give.
Bleach + acid (citric, acetic, phosphoric, oxalic, HCl, descaler)Cl2Chlorine gas. Lung damage at low concentration, life-threatening in a closed space.
Bleach + ammonia (ammonia solution, urine, some window cleaners)NH2Cl, NHCl2Chloramines. Among the commonest domestic poisonings in Sweden.
Bleach + sulfamic acidNCl3Nitrogen trichloride — toxic and shock-sensitive. More dangerous than chlorine gas.
Bleach + hydrogen peroxide or percarbonateO2 + heatViolent evolution of gas, splashes of corrosive liquid.
Bleach + metabisulfiteCl2Chlorine gas.
Bleach + acetone or another solventCHCl3 among othersChlorinated compounds, several of them toxic and long-lived.
Caustic soda or soda ash + aluminium, zinc or tinH2Hydrogen. In a confined space or a stoppered bottle: pressure and an explosive mixture.
Concentrated hydrogen peroxide + acetone—It forms an unstable peroxide compound. Should never be done, on any scale.
Hydrogen peroxide + vinegar in a closed bottleCH3CO3HPeracetic acid. Effective disinfection but corrosive, and the pressure bursts the bottle.
Acid + metabisulfite in a closed roomSO2A pungent gas that triggers asthma attacks.
Concentrated acid + concentrated caustic sodaheatStrongly exothermic. The mixture boils and spits.
Acid + soda ash or bicarbonate in a sealed bottleCO2The pressure bursts the container. Harmless chemistry, dangerous mechanics.
Two unknown ready-made products?You do not know what they contain. The label does not list everything.

Combinations that work

The same logic the other way round. These are the mixtures that genuinely do more together than separately, and that every one of the recipes in section 8 is built on.

Useful combinations
MixGivesSee
Citric acid + APG + xanthanA limescale gel that stays on a vertical surfaceRecipe 03
Soda ash + citrate + APG + IPAAn all-purpose cleaner that works in hard waterRecipe 01
Percarbonate + metasilicatePBW — dissolves burnt-on organic matter without scrubbingRecipe 12
Peroxide + fumed silica + EDTAA stable peroxide gel for retrobrightRecipe 22
NaOH + APG + thickenerOven gel, identical to the bought spraysRecipe 07
Phosphoric acid + xanthanRust conversion gel for vertical surfacesRecipe 15
Citric acid + bicarbonate in an open vesselSodium citrate — a chelator made on the spotSodium citrate
Bicarbonate + salt + aluminium foil + 70 °CElectrochemical silver polishing without abrasionRecipe 18
Soda ash + water + direct currentAn electrolytic rust bathRecipe 16
IPA + ammonia + water + a trace of surfactantStreak-free window cleanerRecipe 08
Petroleum spirit + fumed silicaAn adhesive paste that stays on a vertical surfaceRecipe 21
APG + limonene + glycerol + abrasiveWorkshop hand washRecipe 27
Any chelator at all + hydrogen peroxidePeroxide that actually keeps its strengthEDTA
Any alkali at all + APGAn alkali that wets the surface instead of running off itAPG
Enzyme + water at 40 degrees + timeProtein and smell out of a material that can take neither caustic soda nor bleachRecipe 11
Three rules for improvising safely
  • Never mix across the middle of the pH scale. Acid with acid and alkali with alkali works. Acid with alkali merely neutralises, and you are left with salt water — at best. The only exception is when neutralisation is the purpose.
  • An oxidant and a reductant in the same bottle cancel each other out. Percarbonate and metabisulfite together are wasted powder. The same goes for enzyme and oxidant: the oxidant breaks the enzyme down. Run them one after the other, not at the same time.
  • The additives are always safe. Surfactant, chelator, thickener and glycerol can be mixed into anything at all across the whole pH range without risk. That is where you get the improvement when you do not want to increase the strength.
11

Storage and shelf life

Dry salts are in practice eternal. Liquids and oxidants are not. That is why the powder forms are preferable throughout.

Shelf life once opened
SubstanceFormShelf lifeStored
Citric acidPowderIn practice unlimitedDry, sealed tub. It cakes with moisture but works anyway.
Sulfamic acidPowderSeveral yearsDry. Apart from bleach.
Oxalic acidPowderSeveral yearsDry and locked away if there are children in the house.
Phosphoric acidLiquidSeveral yearsOriginal bottle, PP or HDPE.
Acetic acidLiquidUnlimitedCool, sealed.
Hydrochloric acidLiquidSeveral yearsVentilated, never in the same cupboard as tools or metal.
Ascorbic acidPowder2–3 yearsDark and dry. Broken down by light and air.
Bicarbonate of sodaPowderSeveral yearsDry.
Soda ashPowderSeveral yearsDry. Washing soda crystals lose water of crystallisation and cake together.
Sodium metasilicateBeadsSeveral yearsAirtight. Strongly hygroscopic.
Sodium hydroxideBeadsSeveral yearsAirtight and locked away. It takes up both moisture and carbon dioxide from the air.
Ammonia solutionLiquid1–2 yearsCool and very well sealed. The ammonia evaporates and the solution weakens.
Sodium percarbonateGranules2–3 years drySealed tub, dry. Moisture starts a slow decomposition.
Hydrogen peroxideLiquid6–18 months once openedDark, cool, in the original bottle. Write the opening date on it.
Household bleachLiquidAbout 6 monthsDark, cool, physically apart from everything else.
Sodium metabisulfitePowder1–2 yearsAirtight. Slowly oxidised by the air.
IPA, acetone, ethyl acetateLiquidSeveral yearsSealed, cool, fire-safe cupboard. Never in the sun.
Petroleum spirit, white spiritLiquidSeveral yearsSealed, cool, fire-safe cupboard.
D-limoneneLiquid1–2 yearsSealed and dark. It oxidises to sensitising hydroperoxides.
APG surfactantLiquid1–2 yearsRoom temperature. It goes cloudy in the cold but recovers.
EDTA, sodium citratePowderSeveral yearsDry.
XanthanPowderSeveral yearsDry and sealed. Extremely hygroscopic.
Fumed silicaPowderUnlimitedSealed, or it dusts all over the workshop.
GlycerolLiquidSeveral yearsSealed. It draws water out of the air and dilutes itself.
Activated carbonGranulesUnlimited unopenedAirtight — otherwise it saturates itself on the air in the room for nothing.
Four rules for the cupboard
  • Label everything, at once. Contents, strength, date. An unlabelled bottle is by definition hazardous waste — you will not remember.
  • Never in drinks bottles. That is how children are poisoned, and a PET bottle cannot take caustic soda either.
  • Bleach on its own shelf, in another room for preference. Acids on one shelf, alkalis on another.
  • Solvents cool and apart from oxidants. Never in the garage next to peroxide or percarbonate.
12

Spills, accidents and waste

The dullest chapter and the only one you need to know by heart. Read it once now, not when it has already happened.

If something has just happened

The Swedish Poisons Information Centre, 010-456 6700 — around the clock, for advice in non-urgent cases. 112 in an emergency. Outside Sweden, your own national poisons centre. Have the packaging in front of you when you ring; the first thing they ask is what the product is called and how concentrated it is.

First aid

What applies on exposure
WhereDoDo not
In the eye Rinse immediately with lukewarm water for at least 15 minutes, longer for alkali. Hold the eyelid open with your fingers. Take contact lenses out during the rinsing, not before. Seek medical attention even if it feels fine afterwards. Wait. Rub. Neutralise with something else — that develops heat in the eye.
On the skin Rinse under running water for 15 minutes. Take off clothes and watch while you rinse. Caustic soda feels slippery and needs longer rinsing than it seems to. Neutralise with acid or base. Use ointment or oil before it has been rinsed.
Inhaled Out into fresh air at once. Rest half sitting up. Ring 112 if there is breathlessness or a cough that will not settle — chlorine gas and chloramines can produce symptoms only several hours later. Go back in to air the place. Wait and see whether it passes.
Swallowed Rinse the mouth. Drink a couple of mouthfuls of water or milk. Ring the poisons centre immediately. Induce vomiting. Corrosive substances damage the oesophagus a second time on the way up. Do not give fizzy drinks.
Hydrofluoric acid Rinse, and go to A&E — say “hydrogen fluoride” explicitly. It can arise from leaking lithium cells. The injury often is not felt until hours later, and the fluoride goes on into the tissue in the meantime. Wait because it does not hurt.

Spills

  • Acid — sprinkle bicarbonate or soda ash on until it stops fizzing, wipe up, rinse.
  • Alkali — dilute with plenty of water first, wipe up, then wipe over with dilute citric acid. Never sprinkle dry powder into a pool of caustic soda.
  • Solvents — ventilate, put out anything that could give a spark, soak it up with cat litter or vermiculite. The rags go into an airtight tin or are dried flat outdoors.
  • Oxidant — dilute with a lot of water. Do not mix organic absorbent into concentrated peroxide.
  • Mercury, a lithium cell or something unknown — ventilate, do not touch it, ring the poisons centre.

What may be flushed away

A treatment works can handle dilute and biodegradable. It cannot handle solvents, heavy metals, or large amounts of strongly acidic or alkaline liquid all at once.

  • Fine down the drain, diluted and rinsed after: citric acid, vinegar, soda ash, bicarbonate, sodium citrate, percarbonate, APG, soft soap, enzyme solution, glycerol.
  • Neutralise first, then flush with plenty of water: caustic soda, metasilicate, phosphoric acid, sulfamic acid, hydrochloric acid. Aim for pH 6–9 before it goes down.
  • Never down the drain: acetone, petroleum spirit, white spirit, ethyl acetate, d-limonene, methylated spirits, oxalic acid in quantity, EDTA in quantity, bleach together with anything else, and any mixture whose contents you do not know.
  • To be handed in at the recycling centre as hazardous waste: everything in the point above, plus old or unlabelled bottles, batteries and rags soaked in solvent. Hand them in in the original packaging with the label legible — the staff need to know what it is.

Outdoors a simpler rule applies: do not pour concentrated solution onto a flower bed, a lawn, a storm drain or a ditch. In many cases the storm drain goes straight out into the nearest watercourse without treatment. Do water the planting both before and after working on a deck or a wall, so that whatever runs off anyway is diluted.

13

Buying and equipment

Most of it costs a fraction per kilo if you buy it in the right place. Brewing suppliers are consistently cheapest, because they sell food grade in kilo lots. For the solvents the equivalent is Biltema: acetone, white spirit, methylated spirits and isopropanol 99.5 % sit in the same shop across the country, and deionised water is there too, by the canister.

Where to find it in Sweden · prices are approximate, per kilo or litre
SubstanceBuy fromSearch forApprox. price
Citric acidBrewing supplier, eco shop onlinecitric acid 1 kg75–140 SEK
Sodium percarbonateBrewing supplier, eco shop, janitorial wholesalersodium percarbonate75–120 SEK
Soda ash, anhydrousGrocery, builders' merchant, pool suppliersodium carbonate · soda ash · pool pH increaser40–70 SEK
Bicarbonate of sodaGrocery, pharmacybicarbonate of soda 1 kg30–60 SEK
Sodium hydroxideBuilders' merchant, paint shopcaustic soda · lye · sodium hydroxide beads60–120 SEK
Sodium metasilicateBrewing supplier, chemical wholesalersodium metasilicate · PBW100–180 SEK
Oxalic acidPaint shop, beekeeping supplieroxalic acid · wood bleach150–300 SEK
Phosphoric acidCar accessory and paint shop, brewing supplieracid wheel wash · phosphoric-acid rust converter · StarSan150–250 SEK
Sulfamic acidPlumbers' merchant, brewing supplier, chemical wholesalersulfamic acid · amidosulfonic acid120–200 SEK
Sodium bisulfatePool supplier, builders' merchantpH minus · pool pH reducer · sodium bisulfate 3 kg150–200 SEK
Ascorbic acidBrewing supplier, pharmacy, health food shopascorbic acid 1 kg200–350 SEK
Sodium metabisulfiteBrewing suppliersodium metabisulfite · Campden80–150 SEK
Sodium thiosulfateAmazon, aquarium shopsodium thiosulfate pentahydrate · fixer salt · antichlor 1 kg200–300 SEK
Calcium hypochloritePool suppliershock chlorine granules 70 % · hypocal 5 kg400–500 SEK
Trichloroisocyanuric acidPool supplierchlorine tablets 200 g · chlorine puck · slow-release chlorine 5 kg400–600 SEK
Ammonia solutionPaint shop, builders' merchantammonia solution40–70 SEK
Isopropanol 99.5 %Electronics supplier, pharmacy, Biltemaisopropanol 99.5100–200 SEK
Acetone, white spirit, methylated spiritsPaint shop, builders' merchant, Biltemaacetone · white spirit · methylated spirits (T-röd)40–150 SEK
Petroleum spiritHardware shop, tobacconistcleaning naphtha · Zippo lighter fuel100–200 SEK
Ethyl acetateChemical supplier online, pharmacyethyl acetate150–250 SEK
D-limoneneSoap and cosmetics ingredient supplierd-limonene · orange terpene250–450 SEK
APG surfactantSoap and cosmetics ingredient suppliersugar surfactant · lauryl glucoside · Plantacare150–300 SEK
EDTABrewing supplier, ingredient suppliertetrasodium EDTA200–350 SEK
Sodium citrateBrewing supplier, pharmacytrisodium citrate120–200 SEK
Xanthan gumGrocery, health food shop, brewing supplierxanthan gum200–400 SEK
Fumed silicaComposites supplierAerosil 200 · fumed silica · silica for epoxy300–500 SEK
GlycerolPharmacy, groceryglycerol · glycerine100–180 SEK
Activated carbonAquarium shop, brewing supplieractivated carbon granules150–300 SEK

Equipment

This is the part that actually decides whether home mixing becomes useful or merely approximate. A scale that reads to a tenth of a gram is the difference between a recipe and a guess.

  • A scale with 0.1 g resolution and at least 2 kg capacity. A kitchen scale is not enough for thickeners and chelators, where the dose is a few grams.
  • A second scale with 0.01 g if you mix gels often. Xanthan is dosed in single grams.
  • pH strips 0–14. To verify that the mixture ended up where you thought. An electronic pH meter is not needed in a domestic context and takes more calibration than it is worth.
  • Spray bottles in PP or HDPE with a chemical-resistant nozzle. Ordinary garden sprayers have their seals destroyed by alkali within a few weeks.
  • Measuring cylinders and jugs in PP, a set that is never used for food.
  • Nitrile gloves as standard. Butyl rubber for longer work with acetone and other ketones — nitrile is dissolved by acetone within minutes.
  • Close-fitting goggles, not safety spectacles. For caustic soda and acid work in volume: a face shield over the top.
  • A2P3 respiratory protection for solvents and dust. A P3 filter is enough for weighing powders out.
  • Absorbent material — cat litter or vermiculite — and a bag of bicarbonate plus a bag of citric acid ready for spills in either direction.
  • Labels and a permanent marker. The cheapest safety equipment there is.

Rules worth knowing about

Three sets of rules can catch you out when buying chemicals privately or going out into the garden, and both are easy to trip over when you order in a higher purity than the ordinary retail product.

Explosives precursors. EU Regulation 2019/1148, in Sweden supplemented by the Act (2014:799), forbids private individuals to acquire, import, possess or use products above certain concentrations. Three of them are ones you might very well order in this context:

  • Hydrogen peroxide above 12 % — a licence from MSB is required in Sweden; other member states license or ban. Hair bleach's “40 volume” sits exactly on the limit.
  • Sulphuric acid above 15 % — which battery acid is. It is in none of the recipes here, but it is in many garages.
  • Nitric acid above 3 % — the old industry standard for passivating stainless, now replaced by citric acid. One more reason to use citric acid instead.

Packaging that is covered must be marked to say that purchase, possession and use by private individuals is restricted. Acetone is not forbidden but is on the regulation's second list, where the retailer is obliged to report suspicious transactions — which only means that you may be asked what you want it for on a larger purchase. The details are at MSB.

Particularly dangerous chemical products. The Swedish Chemicals Agency requires a permit for private handling of certain products, mainly those acutely toxic in the higher classes or classified as carcinogenic, mutagenic or toxic for reproduction. Since 1 January 2025 that covers drain openers — that is, products sold for cleaning drains — that contain sodium or potassium hydroxide at concentrations classing them as skin-corrosive category 1A. You apply for the permit at the county administrative board. The definition follows the product and not the substance: caustic soda as a raw material is not affected and is sold as before. What disappeared from the shelf is the ready-made bottle, not the caustic soda. Otherwise nothing here falls into that category at retail concentration, but the limit can be crossed if you order analytical grade. Check with the Swedish Chemicals Agency if in doubt.

Plant protection products

Killing weeds with something you already have at home is nearly always not allowed, and it is not a formality. What decides is the purpose, not the substance: use vinegar or salt with the intention of killing plants and it counts as the use of a plant protection product, and that requires an approval which neither kitchen vinegar nor road salt has. The Swedish Chemicals Agency is explicit about the salt — there are no approved plant protection products in Sweden containing ordinary salt. Products sold as weedkilling vinegar and approved in class 3 with a Swedish registration number may on the other hand be used by private individuals.

Physical methods fall outside the rules entirely: hot water, steam and flaming need no approval. They are also more honest — just like the vinegar they burn the leaves and leave the root alone, so what decides the outcome is that you repeat it, not what you pour on.

The rules change. Check with the authority and do not trust this page to be up to date — it was written at one moment and it ages.

14

If you only buy a few things

Arranged by how much each purchase actually changes what you can manage, not by how often they are used.

Step 1 · the five that make the most difference
SubstanceWhy this one
Citric acidIt replaces every descaler you have ever bought, plus rust stains, passivating stainless and neutralising alkaline residues. Cheap, odourless, food-safe.
Sodium percarbonateDry hydrogen peroxide that keeps for years. Stains, textiles, decking, vessels, retrobright. It replaces both bleach and your old bottle of peroxide.
APG surfactantIt makes everything else work. Stable across the whole pH range, so one bottle covers every mixture in the document.
Petroleum spiritThe best in the world on adhesive residues and tar, and gentle on paint and plastic. No other agent does the same job.
Sodium citrate or EDTAThe chelator you are missing. A couple of grams does more for a mixture in hard water than doubling the surfactant.
Step 2 · when you want to formulate yourself
SubstanceUnlocks
Xanthan gumEvery gel. It turns a spray that runs off into an agent that works for thirty minutes.
Soda ash, anhydrousReal degreasing. Extractor filters, oven trays, pre-wash, electrolytic baths.
Sodium hydroxideHardened fat, drains, ovens, soap. The only thing that bites on polymerised oil.
Phosphoric acidRust treatment before painting. Necessary if you have vehicles or steel projects.
GlycerolIt keeps gels willing to work and solves xanthan's lumping problem.
Step 3 · specialists, buy when the need arises
SubstanceThe only reason
Oxalic acidGreyed decking, iron stains in wood, rust in concrete and textiles.
Sodium metasilicateYour own PBW, and alkaline degreasing where light alloys are involved.
Sulfamic acidHeavy limescale, and descaling stainless without chlorides.
Sodium bisulfateA strong acid stored like caster sugar, at the pool trade's price per kilo. Buy it instead of hydrochloric acid if you do not already have hydrochloric acid.
Fumed silicaPeroxide gel and other agents that have to work for days. Epoxy filler too.
D-limonenePitch, chewing gum, and as a booster in your own agents.
Sodium metabisulfiteChlorine neutralising and oxidation stains.
Sodium thiosulfateThe same job as metabisulfite without the sulphur dioxide. Only if the space is cramped or somebody in the household is asthmatic.
Activated carbonSmells that cannot be washed away.
What you can stop buying

Descaler, oven cleaner, stain remover, all-purpose cleaner, window cleaner, limescale remover, rust converter, silver polish, adhesive remover, machine cleaner and decking wash are every one of them one of the entries above, diluted in water and priced by the decilitre. What you are paying for is the bottle, the thickener, and somebody else having weighed it out for you.

15

Register

The rest of the document is arranged by chemistry. This section is arranged by problem, because that is how you actually get here: you have a stain, not a question about proton transfer. Look up the symptom, get the agent.

How to read the tables

The column what it is is there because it often solves the problem on its own: know that the stain is mineral and you know it should be met with acid, even when your particular variety is not in the list. Avoidcolumn lists what makes matters worse, not merely what is ineffective.

Kitchen
ProblemWhat it isDoAvoid
Darkened copper or brassAn oxide layer, sometimes sulfideRecipe 31 · citric acid with salt, then dry at onceThe silver trick with foil — that only works on sulfide
Limescale in the kettle and coffee makerCalcium carbonateRecipe 02 · citric acid 15–20 g/lScraping — it scratches and gives a key for more
Sour taste in the coffee after descalingAcid residues in the systemRinse three full tanks of clean waterSkipping the rinse
Sticky grease on the cooker hoodPolymerised cooking oilRecipe 06 · check whether the filter is aluminiumNeat soda ash on an aluminium filter
Burnt on the oven floorCharred, hardened fatRecipe 07 · caustic gel in a cold ovenCaustic soda on catalytic enamel — permanently destroyed
A discoloured plastic chopping boardDyes in the poresPercarbonate 30 g/l, 60 °CBleach — it makes the plastic brittle
Brown deposit in a vacuum flaskTannin and coffee oilsRecipe 12 · PBWAn abrasive sponge in a stainless liner
Milkstone in the milk frotherCalcium bound to proteinCitric acid 15 g/l hot, then enzymeAlkali alone — it does not reach the limescale
White powder in the dishwasherLimescale and detergent residuesRecipe 04Citric acid and percarbonate at the same time
Rust spots on a stainless sinkIron contamination from outsideRecipe 19 · citric acid 10 %Hydrochloric acid — it causes pitting
A tarnished pan baseAn oxide layer from overheatingCitric acid 50 g/l, bring to the boilSteel wool on a bright surface
Smell in the fridgeAcidic, volatile breakdown productsBicarbonate of soda open, changed monthlyPerfume that masks it
Black cutlery marks in porcelainA metal deposit, not a stainBicarbonate paste 3 parts powder to 1 part water, rubbed gentlyScouring powder — it dulls the glaze
Bathroom
ProblemWhat it isDoAvoid
Limescale that citric acid cannot manageA hard, old deposit, often with iron in itRecipe 30 · sodium bisulfate 50 g/l, or sulfamic acid on stainlessHydrochloric acid indoors — the vapour attacks everything in the room
A grey film on the shower screenLimescale plus lime soapRecipe 03 · limescale gel, or the phosphoric acid versionWashing-up liquid — it does not dissolve anything mineral
Limescale rings in the toiletLimescale and urine scaleCitric acid 100 g/l overnightBleach after something acidic — chlorine gas
Black spots in the groutMould that has grown into the materialRecipe 24 · if it stays: re-groutTreating it and ignoring the damp
Old silicone bead to be removedCross-linked silicone, cannot be dissolvedCut it loose first, the rest with recipe 32Starting with the chemistry — it only takes the skin
A blocked shower headLimescale in the holesA bag of citric acid 50 g/l, tied on overnightA needle — it widens the holes unevenly
A slow drain in the showerHair bound up in soap scumRecipe 09 · mechanically firstCaustic soda on top of another agent
Yellowed white bathroom plasticDegraded flame retardantsRecipe 22 · retrobrightSanding — the yellowing goes deep
A dull marble worktop with ringsEtch damage, not a stainGround and repolished by a professionalAny acid at all, citric and acetic included
Laundry and textiles
StainWhat it isDoAvoid
BloodProteinRinse cold first, then recipe 11Hot water — it coagulates and fixes it
Red wineAnthocyaninsRecipe 10 · oxygen bleaching 60 °CSalt — the myth does not work
Coffee and teaTanninPercarbonate 20 g/l, soakSoap first — it can fix the stain
GrassChlorophyll, partly fat-solubleA little methylated spirits on the stain, then percarbonateWater alone
Tomato and tomato sauceLycopene — a fat-soluble carotenoid, not water-solubleRinse cold from the back, APG or washing-up liquid on the grease, then Recipe 10. Hang the garment out damp in the sun — UV breaks the lycopene downHot water and a tumble dryer before the stain is gone — heat fixes the carotenoid in the fibre
BananaColourless polyphenols that the enzyme polyphenol oxidase darkens with oxygen — the same chemistry as a browning appleTreat it while the stain is still invisible: ascorbic acid or metabisulfite stops the enzyme. If it has already blackened: Recipe 10Letting the garment lie and dry, and an iron — the polymerisation cannot be reversed
Yellowed underarms from sweatProtein plus aluminium salt from deodorantEnzyme first, oxygen bleach afterBleach — it makes the yellowing permanent
Engine oil in work clothesNon-polar greasePetroleum spirit on the back, paper underneath, then anhydrous soda ash 30 g/lWashing it straight away — it spreads the stain
Rust from a paperclip or a hangerIron oxide in the fibreRecipe 17 · ascorbic acid firstBleach — it fixes the iron
Ink and ballpointDye in a solventIPA drop by drop, paper underneath, change the paper oftenRubbing — it spreads it
Wax and candle greaseSolid fatScrape it cold, iron through kitchen paper, residues with petroleum spiritHot water — it drives the wax in
Chewing gumSynthetic rubberFreeze it hard and break it off, residues with d-limonenePulling at it warm
Whites that have yellowed in storageOxidation of the fibrePercarbonate 30 g/l, 60 °C, overnightBleach on linen and cotton sateen
A stain that went yellow from bleachOver-oxidationMetabisulfite or ascorbic acidMore bleach
A towel that smells musty straight awayBacteria in detergent residues90 °C with 100 g of percarbonate, no fabric conditionerFabric conditioner — it feeds the problem
Bubble solution — brown spots and ringsA cationic polymer from the bubble mix. It is not visible on the garment — the precipitate forms in the wash, when the detergent's anionic surfactant meets itRinse cold before washing. Already washed: rewash with plenty of detergent, or with dishwasher powder, which is non-ionicSkimping on detergent — the precipitate is heaviest where the charges cancel out
Coloured bubble solutionThe dye, on top of the polymer aboveTake the polymer off first, then recipe 10 · oxygen bleaching 60 °CThe tumble dryer before the colour is gone — heat fixes it
Blood or food on wool and silkProtein on a protein fibreRecipe 11, 40 °C at mostPercarbonate and caustic soda — they destroy the fibre
Floors, surfaces and furniture
ProblemWhat it isDoAvoid
A surface to be disinfected, not merely cleanedInfection, drain water, raw chickenClean first, then Recipe 29 · 15 minutes' contact timeSpraying onto a dirty surface — the chlorine is used up by the dirt
A sticky surface on kitchen doorsGrease plus plasticiser out of the finishRecipe 05, carefullyAcetone and spirits on a painted door
Streaks after cleaning windowsToo much surfactantRecipe 08 · 2 ml of APG per litre, no moreCleaning them in sunshine
White rings on wooden furnitureMoisture trapped in the lacquerLow heat and time, otherwise repolishingWater-based cleaning — more moisture
Stickers and price labelsRubber cementRecipe 21 · petroleum spiritAcetone on lacquer and plastic
A grey soap film on a wooden floorLime soap from hard waterA pinch of sodium citrate in the bucketMore soft soap
A grease stain in untreated stoneGrease deep in the poresA poultice — the same technique as concreteAcid on stone containing lime
Shoe marks on tilesRubber deposited on the surfaceRub it off with a clean rubber sole, then all-purpose cleanerAn abrasive on a glazed surface
A chemical spill in a sofaUsually an esterRecipe 25 · alkaline hydrolysis, then carbonMerely masking the smell
Garage, workshop and vehicles
ProblemWhat it isDoAvoid
Road salt on the underbody and paintChloride that holds the moisture thereA lot of water, lukewarm, from underneath. Salt is highly soluble — it is the volume that does the workAcid. It does not take the salt and it attacks both light alloys and bare steel
Dried paint in a brushIt depends entirely on the type of paintAcrylic and latex: IPA or ammonia solution softens it. Alkyd and oil: white spirit while it is wetLetting a two-part paint cure — the brush is then finished
An oil stain in the concrete floorOil down in the pore systemRecipe 28 · a poulticePressure washing first — it drives it in
Surface rust on toolsIron oxideCitric acid 50 g/l, or recipe 16Not oiling it immediately afterwards
Rust in threads and cavitiesRust where no brush reachesRecipe 16 · electrolysisA stainless anode — it gives hexavalent chromium
Rusty sheet metal to be paintedRed rustRecipe 15 · prime the same dayPhosphoric acid on galvanised
Brake dust on wheelsIron particles plus organic matterRecipe 23Strongly alkaline on polished aluminium
Fallout rust — orange specks on light paintIron particles burned into the paintA thioglycolate-based fallout remover, cold surface in the shade, see recipe 23Acid and steel wool — the one etches, the other scratches
Tar spots on the paintBitumenPetroleum spirit on a cloth, brief contact, wash afterwardsAcetone — it attacks the clear coat
White powder in the battery compartmentPotassium hydroxide — alkalineRecipe 26 · citric acid 10 %Soda ash — the wrong direction on the scale
A leaking lithium cellLiPF6, which gives hydrogen fluoride with moistureDry absorbent, ventilate, recyclingWater — it forms hydrofluoric acid
Black hands after the jobOil, soot, pitchRecipe 27 · on dry handsWetting your hands first
Cured epoxy on toolsA cross-linked polymerNothing dissolves it — clean before it curesSaving it until the next day
Weld tint on stainlessA chromium-depleted oxide layerRecipe 19 · passivationLeaving it untreated — it then rusts
Outdoors
ProblemWhat it isDoAvoid
Weeds in paving joints and gravelSeed weeds and perennial rootsHot water or flaming, repeated — thermal methods are permitted physical alternatives. Perennials have to be dug out mechanicallyKitchen vinegar and salt — see Rules worth knowing about
Pool water to be emptied into the ditchFree chlorine kills everything in the receiving waterSodium thiosulfate until the chlorine test turns, and measure before you empty itSimply letting it stand — sunny weather takes days, cloudy longer
A green film on the deckingAlgae and mossRecipe 13 · percarbonateBleach — it raises the fibre
Silver-grey, leached woodDegraded ligninRecipe 14 · oxalic acid, then oilOiling before it has dried for two days
Black streaks at the screwsIron plus tannin in the woodOxalic acid 50 g/l locallyLeaving galvanised parts uncovered during treatment
Rust streaks on pavingIron from furniture legs or reinforcementRecipe 17 · gel on a vertical surfaceAcid on limestone and marble
Cement haze on newly laid tileLime residuesSulfamic acid 30 g/lHydrochloric acid indoors — the vapours corrode
Green growth on cladding and fencesAlgaePercarbonate 30 g/l with APGPressure washing on timber cladding
Aphids on plantsInsects with a waxy layerPotassium soft soap 20 ml/l sprayed onSpraying in sunshine
Electronics and gadgets
ProblemWhat it isDoAvoid
Flux residues on a circuit boardResin and activatorsRecipe 20 · IPA 99.5 %Acetone — it dissolves markings and housings
Old thermal pasteSilicone oil with fillerIPA 99.5 % and a lint-free clothScraping the processor lid with metal
A yellowed retro computerDegraded flame retardants in ABSRecipe 22 · even applicationUneven gel — permanent marbling
A crazed visor or LED lensStress cracksIt cannot be repaired — replace the partIPA on polycarbonate
Cured superglue where it should not beCyanoacrylateEthyl acetate, soak it and be patientBreaking it off
A sticky rubber grip on a toolHydrolysed soft rubberIPA and a cloth, several roundsA solvent that swells the rubber further
Green corrosion on contactsCopper oxide and saltsCitric acid 10 % with a stick, rinse, dry in IPAWater left behind
Odour
OdourWhat it isDoAvoid
Foot odour in shoesIsovaleric acid — acidicPercarbonate 20 g/l, new insoles, alternate pairsVinegar — acid against acid does nothing
The smell comes back when the shoe gets wetThe substances are still in the foamChange the insole and the lining — foam cannot be rinsed cleanWashing the surface again
A musty washing machineBiofilm in the sealRecipe 04, door left ajarFabric conditioner
A cellar smell in textilesMould sporesPercarbonate 30 g/l, 60 °C, dry completelyPacking it away before it has dried
A pet accident on a carpetUrine protein and uric acidEnzyme — the only thing that breaks it downAmmonia — it smells like marking
Smoke in a room or in furnitureVolatile organic compoundsActivated carbon tight up against it, changed onceScented candles and perfume
A chemical smell after a spillUsually an esterRecipe 25Merely airing and hoping
Sulphur in the drainSulfide-forming bacteriaPercarbonate 50 g into the pipe, flush warmBleach after something acidic
The smell comes back every timeThe damp is the cause, the smell the symptomSort out the drying — the chemistry is half the jobTreating it over and over
If it is not in the list

Ask two questions. Is the stain mineral or organic? Mineral — limescale, rust, salt, tarnish — is met with acid. Organic — fat, protein, soot — with alkali. Or is it neither? If it is greasy, sticky or waxy it is neither acidic nor alkaline but non-polar, and then a solvent is what applies. If it is in something porous the answer is always a poultice, whichever of the three it is.