| Quick Facts | |
|---|---|
| Usually washable | Wool, feather, down and polyester fibrefill, if the label allows |
| Never washable | Solid memory foam and latex |
| What to wash instead | The removable zipped cover |
| Foam cleaning method | Blot with a barely damp cloth, never rub or soak |
| Machine settings | Gentle, warm, half detergent, extra rinse |
| Drying | Low or no heat with tennis balls; never for foam |
| Why foam fails | Torn cell structure, plus a core that stays damp for days |
| Best prevention | A washable protector over the topper from day one |
Which mattress toppers are washable and which are not
Loose fill such as wool, feather and fibrefill often is; solid memory foam and latex never are.
Shopping for a specific model? See top-rated mattress topper models — 10 models compared on the specs that decide it.
Sort by what is inside. Wool, down, feather and polyester fibrefill toppers are loose fill held inside a fabric shell, and water can move through them and out again, so many are machine washable when the label permits. Solid memory foam and latex are a single continuous piece, and they behave completely differently. Foam is a network of tiny connected cells, and those cells fill with water in a machine, which makes the topper enormously heavy. The drum then tumbles that weight against itself and the cell walls tear. The damage happens inside where you cannot see it, so the topper looks intact and feels lumpy and dead. Latex behaves much the same. Check the care label before deciding anything, since the label carries the manufacturer's instructions for regular care and it will tell you which of these you own.
Why washing foam ruins it, even when it survives the cycle
Foam holds water deep in the core, so it stays damp for days and grows mould where you cannot reach.
There are two separate failures and the second one catches people who got away with the first. The mechanical failure is the tearing described above. The slower failure is drying. A three-inch slab of foam holds a surprising volume of water in the middle, and air cannot circulate through a solid block, so the core dries from the outside inward over days rather than hours. Meanwhile the outside feels dry and gets put back on the bed. Moisture control governs mould growth indoors, and a dark, still, insulated foam core that stays wet for days is close to ideal conditions for it. You usually smell it before anything else, and by then the growth is inside the material rather than on it. That is the point at which the topper has to be thrown away, so the wash that was meant to clean it is what ends it.
Wash the cover, spot clean the core
Unzip and machine wash the cover; treat the foam itself with a barely damp cloth and mild detergent.
Most decent foam toppers come with a removable cover held on by a zip, and that cover is designed to be washed. Take it off and wash it on the setting its own label specifies, which is usually gentle and warm. That handles the majority of ordinary grime, because the cover is what your sheets and body have been in contact with. For the foam underneath, work locally. Mix a little mild detergent with water, dampen a cloth and wring it out hard so it is barely moist rather than wet, and blot the mark rather than rubbing it. Rubbing pushes liquid deeper into the foam and abrades the surface. Blot again with a clean damp cloth to lift the detergent, then press a dry towel onto the spot to draw moisture back out. Then let it air completely, flat, with air moving around it, before the bed is remade.
Washing the toppers that can take it
Gentle cycle, warm water, half the usual detergent, an extra rinse, and low or no heat drying.
If you have confirmed the topper is washable, treat it like a very large pillow. Check it fits your machine with room to tumble, because a topper crammed into a drum does not clean and can strain the machine. Use a gentle cycle and warm water within the label's maximum. Use around half the normal detergent, since dense fill traps suds deep inside where the rinse cannot easily reach, and trapped detergent is what leaves washed bedding stiff and grey. Add a second rinse for the same reason. Dry on low heat or no heat with a couple of clean tennis balls to stop the fill matting into lumps, and expect several cycles. As with pillows, test by pressing deep into the middle rather than touching the surface, since any coolness there means water is still trapped.
Avoiding the question altogether
A washable protector over the topper takes the sweat and spills, so the topper rarely needs cleaning at all.
The most useful answer is preventative. Put a washable protector on top of the topper, under the fitted sheet, from the first night. It intercepts sweat, skin oils and spills before they reach anything expensive, and it goes through the machine weekly with the sheets. That matters more here than with a mattress, because a topper is the layer closest to you and absorbs the most, and because a foam topper has no way of being properly cleaned once something soaks in. The protector also extends the topper's usable life for a second reason: moisture accelerates the breakdown of foam and encourages odour, and a topper that stays dry reaches the upper end of its three to five year range instead of the lower. Air the bed for half an hour when you change the sheets and the topper will need real cleaning very rarely.