Stains & problems

What you are trying to remove, and what kind of chemistry it responds to. Classifying a stain correctly is most of the work.

Listed alphabetically.

• Algae

  The green film outdoors, and NOT the same organism as the mould indoors. Where it grows is the diagnosis: shade, overhanging trees, or paving that does not drain.

• Antiperspirant residue

  Two different marks from one product. The white transfer is the product itself. The yellow one is a slow accumulation that has been oxidising in the fabric for months.

• Bicycle chain grease

  A tacky lubricant loaded with road grit and metal, transferred as a sharply defined mark. The grit is what makes it more than a grease stain.

• Bird droppings

  Acidic, alkaline in places, and gritty. On vehicle paint in sun it etches within hours, and what remains after washing is a mark in the finish rather than on it.

• Blood

  A protein stain, and the one where the usual instinct — hot water — is precisely wrong. Heat sets it permanently.

• Brake dust

  Hot iron particles embedded into a wheel coating, not dust sitting on it. They corrode where they land, which is why an alloy wheel appears to be rusting.

• Burnt-on food and carbon deposits

  Food heated until it carbonised and bonded to the surface. Time and softening do the work; scouring powder does the damage.

• Candle wax

  A solid at room temperature that behaves as a grease when melted. The carpet trade's four wax entries name a solvent and a professional — and no heat method at all.

• Chewing gum

  Everyone says freeze it with ice. The carpet trade's own entry for gum says break up the solids and vacuum, and never mentions cold at all.

• Chocolate

  The longest treatment sequence in the carpet trade's database — five agents — because it is three kinds of soil at once.

• Cleaning product residue

  What the last clean left behind. It attracts soil, so the surface gets dirty faster — and the usual response is to use more of what caused it.

• Coffee

  A tannin stain that behaves like red wine and unlike grease. Detergent first, then a mild acid — and the order is the finding.

• Coffee oil residue

  The film inside a brewer that makes good beans taste stale. It is an oxidised oil rather than a stain, and descaling does not touch it.

• Crayon

  Pigment in a wax base, which makes it two problems at once — and the wax half is the one that decides the method.

• Creosote

  Not a kind of soot. A flammable tar condensed from damp, oxygen-starved wood burning — and the hardest forms do not answer to a brush at all.

• Dander

  Shed skin, not hair — which is why removing the hair does not remove the smell, and why the vacuum can become the source.

• Dust

  Mostly textile fibres and skin, held by static as much as by gravity — which is why a dry cloth on a plastic surface makes it worse.

• Dye transfer

  Not a spill. Colour walking off one material onto another under pressure and friction, and on pale leather a manufacturer says it WILL happen.

• Egg stain

  Almost pure protein, and the clearest case there is of hot water making the problem permanent rather than smaller.

• Emulsion paint

  A polymer that dried into the fibre — and the trade sequence for it is entirely aqueous, with no solvent step at all.

• Engine oil

  Not simply an oil. Used engine oil carries combustion soot and metal particles, which is why it marks darker and behaves worse than the oil that went in.

• Faeces

  A protein and biological soil where the hygiene question and the stain question have different answers, and the hygiene one comes first.

• Filtration soil

  Airborne particulate the carpet caught while acting as a filter. Nothing walked it in and no amount of vacuuming will take it out.

• Fingerprints

  Skin oils transferred by touch. A greasy soil rather than a dirty one, which is why water alone does not shift them and why they return immediately.

• Food colouring

  A concentrated water-soluble dye with nothing else in it. Nothing has to be emulsified or dissolved — the only question is whether the surface has taken the colour up.

• Frass and pest residue

  The powder, cast skins and webbing left by something that has been eating the fibre. The deposit is the least of it: the material it came from has gone.

• Fruit juice

  Anthocyanin pigment plus sugar and acid. The sugar is the part that turns an invisible dry mark into a brown one months later.

• Glue and adhesive

  A polymer that set where it landed. Solvent-first — and the solvent that dissolves it also dissolves the carpet's backing adhesive.

• Grass

  Four agents deep — solvent, detergent, vinegar, then ammonia — because it is pigment, sap and soil arriving together.

• Gravy stain

  Fat, protein and starch in one deposit, and they need opposite treatments. The trade order is solvent first, and it is the reverse of the instinct.

• Grease

  Fats and oils, which water alone cannot lift. Removed by surfactants, by heat, by solvents, or by alkalis that convert the fat into soap.

• Hair

  Not a stain and not really a soil — a keratin fibre that tangles, holds everything else, and defeats every wet method by floating.

• Hair dye

  Designed to bond permanently to a protein fibre and developed with an oxidiser. On a surface that is also protein, that design is the problem.

• Hairspray residue

  A polymer film built up by overspray, usually noticed as stickiness on a floor or mirror long before anyone connects it to the can.

• Heat tint

  The rainbow or brown bloom on stainless steel that has been heated. Not a deposit and not dirt: the metal's own surface oxide, thickened by heat.

• Ink

  A dye carried in a solvent, so it responds to a solvent — and the trade sequence ends somewhere most household advice starts.

• Insect residue

  Protein, and therefore a stain that heat sets. A summer bonnet is a protein deposit baked onto a clear coat by the engine and the sun.

• Iron staining from water

  Water itself carrying the stain. Above three-tenths of a part per million, the supply is the source of the mark.

• Label residue

  Pressure-sensitive adhesive left behind when the paper tears away. It stays tacky by design, which is why it collects dirt and turns grey.

• Limescale

  A hard, chalky calcium carbonate deposit left by hard water. Dissolved by acids, essentially untouched by detergents.

• Lipstick and cosmetics

  Pigment suspended in wax and oil, which is why the trade sequence leads with a solvent rather than with detergent.

• Makeup

  An emulsion of oil, pigment and often silicone, formulated to stay put on skin. Two of those three need different treatments, in the right order.

• Mildew

  The flat, powdery surface growth that appears on damp fabric, grout and shower curtains — and the carpet trade's procedure for it names no bleach at all.

• Milk stain

  Protein and fat in water, and the reason a dried milk spill smells long after the mark has gone is that the protein is still there.

• Mineral salt soil

  The soil that alkaline cleaners cannot touch. It needs acid, which is why the strongest degreaser in the cupboard does nothing to it.

• Moss and lichen

  Three different organisms treated as one green problem. Where they grow tells you more about the fix than any product does.

• Mould

  A living growth, not a stain. Killing it and removing the staining are two separate jobs, and neither addresses the moisture that caused it.

• Mud

  The one stain where the first move is mechanical and the chemistry barely matters — and where the folk advice to let it dry first is not what the trade body says.

• Mustard stain

  Coloured by turmeric in most prepared mustards, and curcumin is a pH indicator — which is why an alkaline cleaner turns a yellow mark red.

• Nail varnish

  A pigmented lacquer that dries to a hard film. The solvent that removes it is the strongest one most households own, and it attacks plastics.

• Oil and grease on textile

  The stain where the trade guidance switches from water to solvent — and the switch brings a warning the water route does not have.

• Oil-based paint

  Cures by oxidation into a film that no water-based treatment touches. Wet or dry is the whole question, and the window is a few hours.

• Pencil marks

  Graphite is a particulate, not a dye. Nothing dissolves it, which is why the procedure for it skips detergent and goes straight to a solvent.

• Permanent marker

  Dye in a solvent carrier, designed to resist water. It is the only stain in the carpet database whose procedure begins by telling you to stop.

• Perspiration

  Sweat itself has almost no smell. What you can smell is bacteria eating it — and which bacteria depends on what the garment is made of.

• Phenolic yellowing

  A yellow patch exactly the shape of the rug that was lying on it. The carpet made the colour itself, because that patch could not breathe.

• Pollen

  A seasonal particulate that is part of ordinary dust for most of the year and overwhelms it for a few weeks. Dry removal first, because wet pollen stains.

• Protein soil

  A soil class rather than a stain. Alkali removes it, heat welds it on, and almost every household mistake with it is a temperature mistake.

• Red wine

  A pigment stain from anthocyanins and tannins. Responds to oxidising bleaches rather than to detergents, and gets much harder once dried or heated.

• Road salt

  A white tidemark on boots, carpet and car sills that is also actively corroding whatever it is sitting on.

• Rust

  Hydrated iron oxide from corroding iron or steel. Distinguish a surface deposit, which cleans off, from active corrosion of the item itself, which does not.

• Silicone residue

  Left by most furniture polishes, invisible, and present even after a finish has been stripped to bare wood. It is discovered on the day somebody tries to refinish.

• Skin oil

  The soil that arrives everywhere a person touches, gets darker as it ages, and is the reason a clean-looking surface still feels tacky.

• Soap scum

  Not scale and not dirt: a metal soap formed when hard water meets true soap. It is the reason a shower screen films over in one house and not another.

• Soot

  Carbon particles from incomplete combustion. Largely inert, so it is lifted dry rather than dissolved — and disturbing it dry is itself an exposure.

• Sticky plastic

  The commonest cleaning problem that is not dirt. The tackiness is the plastic's own additive arriving at the surface, which is why wiping it off works for a week.

• Sugar and lactose residue

  The soil class that water alone removes — until it is heated, at which point it becomes one of the hardest things in the kitchen.

• Sunscreen

  Two stains in one bottle: an oily film, and a UV filter that forms a coloured complex with the iron in your water. The second one is why the mark comes out orange.

• Tarnish

  Unlike a stain, tarnish is made of the very surface it sits on. Removing it always removes metal.

• Tea

  A tannin stain treated entirely without solvent — detergent, then a mild acid. The absence of a solvent step is the finding.

• Tobacco residue

  A sticky, yellow-brown tar film deposited everywhere at once. It is the reason a room smells after everything visible has been cleaned.

• Tomato stain

  Carotenoid pigment in an acidic, oily sauce. The pigment is fat-soluble, which is why washing in water sets what looks like an easy stain.

• Tree sap

  A resin that hardens on exposure and bonds tightly to what it lands on. Left on paintwork in sun, it etches rather than merely sticking.

• Urine

  Two problems in one: a visible mark that ordinary cleaning removes, and an odour that survives it. The second is why this stain has a reputation.

• Verdigris

  The green corrosion product on copper and brass. On a roof it is protective; on a tap, a pan or a fitting it is a symptom of trapped moisture.

• Vomit

  Mechanical first, then four agents. The one thing the trade sequence does not mention is the smell, which is the reason most people are cleaning it.

• Water marks

  What hard water leaves behind when it evaporates instead of being wiped away. A mineral film, not dirt, and the fix is at the drying stage.

• Water-borne film

  The haze that appears after cleaning rather than before it. What is left behind when water evaporates is not dirt you missed.

The mechanism decides the treatment, not the name of what spilled. Coffee and red wine are one class; rust and limescale look alike on a bathroom surface and need opposite chemistry from the same acid family.