Carpet Cleaning · Guide
Forty stains, the chemistry behind each one, and an honest verdict on what lifts — written from what our technicians actually do in London homes.
Almost every carpet stain is decided in the first sixty seconds, long before anyone reaches for a product. This guide covers three things: exactly what to do the moment something goes on the floor, which chemistry actually lifts each of the forty stains in the A–Z below, and an honest account of the handful that nobody — professional or otherwise — can bring back.
It is written from what our technicians actually do in London homes every week, put in writing rather than kept in a van. That includes the parts nobody sells: the stains where the best advice is to stop, the household tricks that quietly make things worse, and the difference between a stain sitting on a fibre and damage where the colour has already gone.
First response
1. Blot — never rub
Press a folded white cloth or plain kitchen roll straight down onto the spill and lift. Repeat with a dry section until no more transfers.
Why: Rubbing untwists the pile and leaves a permanently fuzzy patch, and it pushes the spill sideways and downwards at the same time.
2. Work from the outside in
Start at the edge of the mark and move towards the middle on every pass.
Why: Working outwards enlarges the stain into a ring that is far harder to blend back than the original spot.
3. Use a white cloth or plain kitchen roll
No patterned tea towels, no coloured cloths, no printed kitchen roll.
Why: A damp coloured cloth transfers its own dye into wet carpet — we are regularly called to a blue smear left by the towel, not the spill.
4. Cold water first, always
Dilute with cold water before you reach for any product, and only then decide what the stain is.
Why: Heat cooks protein stains such as milk, blood and egg permanently into the fibre, and there is no route back from that.
5. Weight and wait on big spills
For a large liquid spill, cover with a thick pad of kitchen roll, stand a heavy book on it and leave it for an hour.
Why: Capillary action pulls liquid up out of the backing and underlay, which is where the stain would otherwise wick back from days later.
6. Test every product on a hidden patch
Inside a wardrobe, under the sofa or on an offcut — apply, wait ten minutes, blot with white cloth and check for colour transfer.
Why: Most permanent damage we are called out to was caused by the product, not the spill.
7. Never apply heat to an unknown stain
No steam cleaner, no hairdryer, no hot water until you know which family the stain belongs to.
Why: Heat sets protein and drives grease deeper; on an unknown stain it is a one-way bet you can only lose.
Know your enemy
Acid side, cool water, never soap first.
Wine, tea, coffee, fruit juice and beer are plant tannins. They are water-soluble while wet, which is why speed matters more than product. Treat them acid-side — a splash of white vinegar in cool water, or a dedicated tannin spotter — and rinse. Alkaline detergents and soap-based sprays set tannins and leave a yellow shadow that gets harder to shift every week it sits.
Cold water and enzymes. Heat sets it permanently.
Blood, milk, egg, vomit, urine and most food spills are protein. Protein coagulates when it is heated, exactly like an egg hitting a pan — once cooked into the fibre, it is there for good. Cold water only, then an enzyme cleaner that digests the residue rather than dissolving it. Never take a steam cleaner or a kettle to an untreated protein stain.
Absorb the bulk first, then a solvent or surfactant.
Cooking oil, butter, make-up, shoe polish and candle wax will not dissolve in water — plain water spreads them and drives them deeper into the pile. Lift the bulk with a spoon or an absorbent powder, then break the residue with a solvent spotter or a drop of washing-up liquid in warm water. Grease stains that are left attract dry soil, which is why they darken over weeks.
The dangerous family — wrong move and you set it for good.
Ink, curry, hair dye, felt tip, fake tan and some cordials carry a dye designed to bond with fibre. That is the whole point of a dye, and your carpet is a fibre. Blot, do not flood, keep the area small, and stop early — most permanent carpet damage we are called out to is a dye stain someone scrubbed with the wrong product for twenty minutes. This family is where a professional earns their money.
Rule of thumb for a mystery stain: if it came from a plant, treat it as tannin; if it came from an animal or a person, treat it as protein and keep everything cold; if it feels slippery or darkens the pile without colouring it, treat it as grease; and if it is a colour that was designed to stay a colour, treat it as dye and stop early.
A–Z
Type what was spilled — or pick from the list — for the first response, the one thing not to do, and an honest verdict on what a professional can lift.
Pick a stain above for a quick card, or scroll the full A–Z below — all forty entries are on this page.
Plant tannin carrying anthocyanin pigment — water-soluble while wet, oxidising to brown as it dries.
Wool caution. Never use oxi or bleach-based wine removers on wool; they strip dye. Cool water and a WoolSafe tannin spotter only.
A near-colourless tannin with sugars that turn sticky and attract soil as they dry.
Tannin plus malt sugars and yeast — the smell is the yeast, not the colour.
Tannin, and with milk in it a protein stain as well — two chemistries in one spill.
Wool caution. Wool takes tannin readily. Treat it within minutes and keep the moisture low.
The purest tannin stain there is — the same compound that stains a mug brown.
Caramel colouring, phosphoric acid and a lot of sugar.
Natural anthocyanin dye — blackcurrant and cherry behave like a deliberate fabric dye.
Cocoa solids and cocoa butter — a pigment stain riding on a grease stain.
Curcumin — a genuine dye, oil-carried, and one of the most stubborn stains in any home.
Wool caution. On wool, reducing agents must be used with care and neutralised properly — this is not a DIY chemistry set.
Lycopene pigment in an oily, acidic base — tannin behaviour with a grease component.
Triglyceride oil, insoluble in water, which is why plain water only spreads it.
Dairy fat with a protein fraction — grease first, protein second.
Albumin protein — it literally cooks.
Casein protein and fat — the visible mark fades but the smell does not.
Haemoglobin protein — bright red when fresh, oxidised brown once dry.
Wool caution. Skip peroxide entirely on wool. Cold water and an enzyme approved for protein fibres only.
Protein plus stomach acid — the acid attacks carpet dye as well as staining it.
Urea and uric acid salts — the salts are the smell, and they reactivate in humidity.
More concentrated than human urine, alkaline as it ages, and cat urine carries felinine which breaks down into sulphur compounds.
Protein and bacteria — a hygiene job as much as a stain job.
Mineral soil suspended in water — a dry particle problem once it dries.
Chlorophyll — a natural dye bound to a protein carrier.
Oil-based dye in a solvent carrier — it dissolves in alcohol, not water.
Water-based dye, sometimes iron-gall — soluble while wet, far harder once dry.
Pigment in an alcohol-resin base, formulated to be permanent on porous surfaces.
Usually a water-based dye, and usually a bright one designed to be seen.
Pigment held in a paraffin wax — grease first, colour second.
Paraffin or soy wax, often with a strong dye in coloured candles.
Wool caution. Wool tolerates the iron method better than synthetics, but keep the heat low and the paper moving.
A synthetic rubber base — sticky when warm, brittle when frozen.
Nitrocellulose lacquer with heavy pigment — it sets into a plastic film around the fibres.
Wool caution. Wool tolerates solvent better than acetate, but the dye reduction still needs patch-testing.
Pigment suspended in oil and wax — a grease stain wearing a colour.
Carbon black pigment in a wax and polymer base, often water-resistant by design.
DHA reacting with any protein it touches, plus a cosmetic guide colour.
Wool caution. Wool is a protein fibre, so fake tan tans it. Treat within minutes or expect a permanent warm tone.
Oxidative dye engineered to bond permanently with protein fibre, usually with a developer alongside it.
Wool caution. On wool, hair dye does exactly what it was designed to do. Call before experimenting.
Pigment in an acrylic binder that cures as it dries — the clock is the enemy.
Pigment in an alkyd resin that needs white spirit, not water.
Depends entirely on the glue: PVA is water-based, superglue is cyanoacrylate, and contact adhesive is solvent-based.
PVA glue cross-linked with borax, plus a very determined food colouring.
Iron oxide — a mineral deposit rather than a soil, so cleaning products do nothing.
Wool caution. Acid rust removers can strip wool dye. This one is worth handing over rather than testing.
Heavy pigment in wax and solvent — designed to stay on fibre.
Not a stain at all. Bleach has destroyed the dye — there is nothing sitting on the fibre to remove.
Stain beyond a cloth and cold water? Get a fixed price for carpet cleaning before you try anything stronger.
Honest comparison
The short version: many fresh stains are absolutely DIY-winnable, and you should not pay anyone for a cup of coffee spilled ten minutes ago. Professionals earn their fee on set-in, unknown, large or repeated stains, and on delicate fibres where the wrong product costs more than the clean.
The genuine differences are equipment and control. A heated extraction rinse puts clean solution into the pile at pressure and pulls it straight back out with the soil, rather than leaving a damp detergent residue behind. Chemistry is used at measured dilutions with a proper dwell time, so it has long enough to work and is removed before it can affect the dye. Treated areas are pH-balanced afterwards, which is why a professionally cleaned patch does not resoil faster than the carpet around it — the single most common complaint after a DIY spot clean.
Beyond that: enzyme flooding at volume for urine salts, so the treatment reaches as deep as the urine did; graduated solvent work on dye stains, where the aim is controlled reduction rather than one aggressive attempt; and a spotting kit with tannin, protein, solvent and reducing agents in it, so a mystery stain gets three considered attempts instead of one hopeful spray.
Straight answers
Four categories are honestly beyond guaranteed removal, and any cleaner who promises them on the phone before seeing the carpet is telling you what you want to hear.
Set-in dye — old curry, hair dye, some inks and dark cordials — has chemically bonded with the fibre. Good chemistry reduces it, often dramatically, but the dye is now part of the carpet rather than sitting on it. Bleach marks and colour loss are the absence of dye, and no cleaning restores something that is not there. Cigarette burns and heat glazing are melted or destroyed fibre, which is a fitter's patch repair. And anything that has physically damaged the pile — heavy scrubbing, solvent burn, acid dye-strip from vomit — is damage, not soiling.
A quoted price that assumes every stain will vanish is usually a bait price that grows once the technician is in the hallway. The right conversation is the other way round: what will almost certainly come out, what will improve, and what will not move at all — before you book.
Compare quotes against our published price list — a figure far below it usually grows once the technician is in the hallway.
Fibre first
Wool is a protein fibre, which makes it behave more like your own hair than like nylon. Supermarket oxi sprays and high-alkaline all-purpose cleaners are formulated for robust synthetics; on wool they strip the natural lanolin, dull the surface, and can bleed dye out of one tuft into the next. Over-wetting causes shrinkage and felting, and cellulosic browning pulls yellow-brown compounds out of the backing and up to the tips as it dries.
The rules are short. Cool water, never hot. pH-neutral or WoolSafe-approved chemistry only, and no oxygen bleach. Keep moisture low and dry fast with airflow. Blot rather than agitate, because felting is mechanical damage you cannot reverse.
Sisal, seagrass, jute and coir are stricter again: they mark permanently with water, so the honest answer for a wet spill on a natural-fibre floor covering is to blot, absorb and call somebody who carries a fibre-identification kit. A dry compound clean is the only safe route, and it is better to be told what it cannot achieve than to find out with a bucket.
Print it
Know when
Three honest triggers, and if any one of them applies, stop and put the cloth down.
Book a technician near you
Questions
No — it is one of the most persistent myths in cleaning. White wine is also acidic and also contains tannin and sugar, so at best you dilute one stain with another and leave sugar in the pile that attracts soil for months. Cool water and blotting does everything white wine would do, without adding a second spill. If you want a household mix that genuinely helps, use a tablespoon of white vinegar and a teaspoon of washing-up liquid in 500ml of cool water.
Salt draws some liquid up while it is still wet, which is why it looks like it is working, but it also drives pigment down into the backing as it dissolves and it leaves a gritty residue that abrades the pile. Professionals do not use it. A thick pad of white kitchen roll with a heavy book standing on it pulls liquid out of the backing far more effectively and adds nothing to the carpet.
Often, yes — it depends entirely on the family. Old tannin stains such as tea and coffee respond well to acid-side chemistry and controlled heat even years later. Old protein stains usually clean up with enzyme treatment unless heat has already set them. Old dye stains such as curry and hair dye reduce rather than disappear. And if the mark is bleach or colour loss, age is irrelevant — the dye is gone and only re-dyeing or patching will change it.
That is wicking. The spill reached the backing or the underlay, the surface was cleaned, and as the deeper moisture evaporated it carried the remaining stain back up to the tips of the pile. It is the classic sign of a spot clean that treated the top third of the carpet only. The fix is a proper rinse and extraction that reaches as deep as the original spill, followed by weighted drying — not another surface spray.
Oxi-type products are formulated for robust synthetic carpet, not for wool. On wool, oxygen bleach and high-alkaline chemistry can strip lanolin, dull the pile and lift dye, and the damage is not reversible by cleaning. If your carpet is wool or a wool mix, use cool water, blotting and a WoolSafe-approved product only — and always test on a hidden patch first. If you are not sure which fibre you have, that uncertainty is itself a reason to stop.
By treating volume, not surface. We locate the full extent with a UV lamp and a moisture meter, then flood the area with an enzyme treatment in roughly the volume the animal produced so it reaches as deep as the urine did, give it a proper dwell time, and extract sub-surface. Odour comes from uric acid salts, which is why perfumed sprays fail and why the smell returns on humid days. Where urine has reached the underlay or the floorboards, no surface clean fixes it and we say so.
Not by cleaning. A bleach mark is dye loss: the colour has been chemically destroyed, so there is nothing left on the fibre to remove. The two real options are spot re-dyeing by a colour-repair specialist, who mixes to match the surrounding carpet, or a patch repair cutting a piece from inside a wardrobe or from an offcut. Both are trades we refer out, and either is a better use of money than any product promising to restore colour.
Keep three things rather than one miracle spray: a bottle of plain white vinegar for tannin stains, an enzyme cleaner for protein and pet accidents, and a small bottle of surgical spirit for ink, make-up and grease. Add a roll of plain white kitchen roll and a couple of white cloths. That kit covers the overwhelming majority of household spills, costs less than one branded bottle, and never makes a stain worse through the wrong chemistry.
Only once you know the stain family, and never on an untreated protein stain. Domestic machines heat the water, which is exactly wrong for milk, blood, egg, vomit and urine, and they put down far more water than they recover — which is how wicking starts. For a fresh spill, blotting and a correctly matched spotter beats a machine every time. Save the machine for general soiling, and empty and rinse it properly or it will re-deposit old soil.
Within the first minute for liquids, and within the hour for anything oily or dye-based. Fresh spills sit on the fibre surface, where blotting removes most of the material before any chemistry is needed. As it dries, the stain migrates into the pile and towards the backing, oxidises, and in the case of dyes begins bonding with the fibre. The difference between minute one and hour twelve is usually the difference between a complete removal and a permanent shadow.
Still looking at the stain? Send us a photo and we will tell you honestly whether it is worth a call-out.
