How to clean a mattress

So the honest structure of mattress cleaning is: prevent, then treat the surface only, then dry completely. There is no home deep clean.

And one fact governs the economics of all of it: a stain voids most mattress guarantees absolutely. Which makes a protector, at 20 to 40 pounds, the best value purchase in the bedroom.

Why a mattress cannot be properly dried at home

This is the fact that decides everything else on this page, and every stain page on this site links back to it, so it is worth setting out properly rather than as a warning.

A mattress is built to take moisture in and is not built to let it out. The ticking and the quilting are absorbent by design, because they have to cope with the water vapour you give off every night. Below them sits either foam, which holds moisture in its cell structure, or a spring unit wrapped in fibre pads, which holds it in the fibre. Both are sealed inside a cover that does not open, and neither can be reached, wrung out or taken apart.

So liquid travels in under its own weight in seconds, and leaves only by evaporating from the surface. Anything below the first centimetre or two has to migrate upward before it can go anywhere at all, which takes hours for a damp patch and a day or more for a real soaking. A face that feels perfectly dry to the hand routinely has wet fillings underneath it, and there is no way to look.

That gap between a dry surface and a damp core is the whole problem. What sits in the gap is warm, dark, enclosed and wet, which is precisely the condition mould needs, and mould inside a mattress cannot be removed. You can treat the face of a mattress; you cannot get inside one. So a mattress that grows mould internally is finished, which is a considerably worse outcome than the stain that started the job.

Three rules follow, and they are why the stain guides on this site read as cautiously as they do. Use the least liquid that will do the work. Add no heat, which dries the face faster than the core and seals the damp in under it. Allow far longer for drying than seems reasonable. The mechanics of doing that, including how long each kind of wetting really takes, are on how to dry a mattress.

The routine that keeps a mattress clean

Note what is absent: wet cleaning. The protector is the washable part of the system, and the mattress is the part you keep dry.

Vacuuming is worth doing properly. Use the upholstery tool, work in overlapping passes, and do the sides and the seams, where debris collects and where a vacuum actually reaches.

Dealing with a spill, in order

Act immediately. Almost everything is easier wet than dry, and most of the difficulty in stain removal is that the stain has set.

Blot, do not rub. Press a dry towel down hard and lift. Rubbing pushes liquid deeper and spreads the mark outward, which turns a small problem into a large one.

Use as little liquid as you can. A lightly damp cloth, never a soaked one, and never pour anything onto a mattress.

Work from the outside inward, so you do not spread the edge of the mark.

Dry it completely. This is the step that matters most and the one people skip. Open a window, put a fan across the surface, and leave the mattress uncovered and unmade for as long as it takes. Do not put bedding back on a damp mattress.

Specific stains

Blood. Cold water only. Heat sets protein, so warm water makes a blood stain permanent. Blot with cold water, and for a set stain an enzyme cleaner applied sparingly works where detergent does not.

Urine. Blot as much as possible first. An enzyme cleaner is genuinely better here than anything else, because it breaks down the compounds that cause the odour rather than masking them. Bicarbonate of soda afterwards helps with residual smell.

Sweat and yellowing. Usually not a stain so much as accumulated body oils, which is why it covers a broad area rather than a defined mark. It responds to enzyme treatment and prevention rather than scrubbing.

Vomit. Remove solids, blot, enzyme cleaner, dry thoroughly. Ventilate the room.

In every case: test on a hidden area first, usually the underside near a corner, and use the minimum liquid that works.

What never to put on a mattress

A steam cleaner. It drives moisture deep into the fillings and the spring unit, which causes mould and rust. Manufacturers frequently prohibit it, and using one can void your guarantee. This is the single most common way people destroy a sound mattress while trying to help it.

A carpet washer or wet vacuum. Same problem, more water.

Bleach or strong solvents. They damage foam and fabric and can discolour permanently.

Large amounts of bicarbonate of soda left for hours. It absorbs moisture, and then you have to remove all of it. What stays in the fabric attracts more moisture later. A light sprinkle, an hour, and thorough vacuuming is the sensible version.

A hairdryer held close. Heat can damage foam. Ambient airflow from a fan is better and safer.

Smells, damp and mould

A mattress that smells musty rather than of a specific spill usually has a moisture problem rather than a dirt problem, and cleaning it makes that worse.

Air it thoroughly, ventilate the room daily, and check what it is sitting on. A solid platform base collects moisture underneath where nothing can dry it, which is also why a mattress on the floor develops mould on its underside within weeks.

You lose a significant amount of water vapour every night and much of it passes into the mattress. On slats it escapes downward; on a solid deck it does not.

Visible mould inside or on a mattress is the end of it. You cannot reliably remove mould from within fillings, and a mattress at that stage should be replaced rather than treated.

Prevention, which is the only strategy that works

Read the sections above together and the conclusion is uncomfortable: all of it is damage limitation. The only part of mattress cleaning with a genuinely good outcome is the part you do before anything has been spilled, and a breathable protector fitted from the first night turns every incident on this page into a wash load.

Which one to buy, why breathability rather than waterproofing alone is the specification that matters, and how to measure the depth before ordering, are set out in full on the best mattress protectors.

No food or drink in bed is unglamorous advice that prevents more guarantee claims than anything else on this page.

Before you clean anything under guarantee

If the mattress is under guarantee and visibly damaged, photograph it and speak to the retailer first. Cleaning can alter the evidence, and steam cleaning specifically can void the cover.

Your statutory rights sit with whoever sold it to you rather than the manufacturer. Under the Consumer Rights Act 2015 goods must be of satisfactory quality and last a reasonable length of time, and you have up to six years to bring a claim in England, Wales and Northern Ireland, five in Scotland.

Keep the proof of purchase and the date, because after the first six months the burden of proof shifts to you. This is general information rather than legal advice, and Citizens Advice is the right starting point for a specific situation.

Related reading

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