· Léa Vasseur
How to wash a memory foam pillow
This is the single most searched question about these pillows, and the answer that circulates is usually half of one. Below: what actually happens inside the foam when it gets wet, what to do instead, how to deal with a stain, and how to dry the thing if it has already been soaked.
Why the machine destroys it
Memory foam is an open-cell structure — millions of tiny connected chambers whose walls are what give the material its slow, even give. Three things happen in a washing machine, and all three are permanent.
Water fills the cells. The foam absorbs several times its own weight and becomes a heavy, saturated block. That weight alone starts tearing walls before the drum has even begun to turn.
The spin cycle shears it. A saturated block spun at speed is being pulled apart from the inside. The damage is invisible from the outside: the pillow comes out looking like a pillow and behaves like a sponge that has lost its spring.
Drying leaves dead zones. Water trapped in the middle takes days to leave. In the meantime it compresses under its own weight, and those regions come out flatter than the rest and stay that way. You end up with a pillow that has a valley where none was designed.
None of it is reversible. A memory foam pillow that has been through a machine is a pillow to replace, which is why the instruction is worth taking literally rather than as a manufacturer being cautious.
What to wash instead: the cover
Any decent memory foam pillow ships with a cover that unzips. That cover is the part that touches you, absorbs the sweat and the skin oils, and needs washing — which is convenient, because it is also the only part that can be.
| Step | Detail |
|---|---|
| Frequency | Every two to four weeks, more in summer |
| Temperature | 86 °F / 30 °C, gentle cycle |
| Detergent | Ordinary, no bleach, no fabric softener — softener coats the knit and closes the airflow you paid for |
| Drying | Air dry. A tumble dryer shrinks a knitted cover and it will not go back on |
| Putting it back | Only once completely dry. Damp fabric against foam is how a smell starts |
An ordinary pillowcase over the top of the cover is worth using. It takes most of the wear, it goes in with the rest of the bedding, and it doubles the interval between cover washes.
Cleaning a stain on the foam itself
Sometimes something gets through. The method is damp, never wet, and it works on the surface only.
- Mix a teaspoon of mild detergent into a bowl of lukewarm water.
- Dip a cloth and wring it out until it is barely damp. If it drips, it is too wet.
- Dab the stain — do not rub. Rubbing pushes liquid deeper and abrades the surface.
- Go over the same spot with a second cloth dampened in clean water, to lift the detergent.
- Press a dry towel onto the area to draw the moisture back out.
- Leave the pillow to air, flat, away from direct sunlight, until the spot is completely dry to the touch.
For a smell rather than a mark, dry is better than wet: sprinkle baking soda over the foam, leave it for a few hours, and vacuum it off with an upholstery attachment. It draws out odor without introducing a single drop of water.
Airing, which does more than washing ever would
Most of what makes a pillow feel stale is moisture — a sleeping adult loses a surprising amount of it through the night, and a good deal of that ends up in the pillow. Foam does not breathe as freely as a fiber filling, so it holds onto it.
Twenty minutes with the pillow off the bed, cover off, near an open window, does more for it than any cleaning product. Once a month, give it a few hours. Away from direct sun: ultraviolet light yellows memory foam and makes it brittle, and a pillow left on a sunny windowsill ages faster than one used every night.
If it has already been soaked
It may be recoverable, and the odds depend entirely on how patient you are willing to be.
Press — do not wring — as much water out as you can between towels, changing them as they saturate. Then lay the pillow flat on a dry towel in a well-ventilated room, and turn it every few hours. A fan pointed at it helps considerably. Depending on the density, full drying takes anywhere from one to three days.
What decides the outcome is whether it dries all the way through before mildew starts. A pillow that still feels cool and heavy in the middle after two days is holding water in the core, and at that point the smell is coming whatever you do. Heat is not a shortcut: a hairdryer or a radiator melts the cell walls and leaves a hard patch.
Things worth not doing
- Dry cleaning. The solvents break foam down. Dry cleaners will usually refuse a foam pillow, and the ones who accept should not.
- Bleach or a steam cleaner. One dissolves the material, the other forces hot water into it.
- The dryer, on any setting. Including “air fluff” — the tumbling alone tears saturated foam.
- Sitting it on a radiator. Heat hardens the cells; the pillow comes back stiff in patches and never recovers its give.
How long the pillow should last if you look after it
Considerably longer than a fiber filling, which packs down within months. High-density memory foam holds its ability to spring back for several years, and the wear sign is easy to read: press a fist in and count the return. Three to five seconds is healthy. An impression still visible after ten seconds means the density has gone, and no amount of cleaning brings that back.
The other tell is the morning: if the shape of your head is still there when you get up, the foam has stopped returning. More on what density does and how it fails on the memory foam page.