Why You Cannot Wash a Memory Foam Pillow
Almost every care label on a moulded foam pillow says the same thing, and the reasons are worth knowing because the failure is permanent.
What Water Does to It
Memory foam is an open-cell polyurethane structure. Submerged, it absorbs an enormous quantity of water and becomes extremely heavy.
Agitation in a machine then tears that saturated structure apart. The foam does not recover: it comes out lumpy, torn or crumbling.
Even where it survives mechanically, the water is the problem.
Drying Is the Real Issue
- Water penetrates the entire block, not just the surface
- Drying it fully can take days
- Heat damages the foam, so a tumble dryer is not an option
- Foam that is damp inside grows mould where it cannot be seen
- The first sign is a smell weeks later, by which point it is finished
Care guidance stating that the core should only ever be aired and never soaked, of the kind published at bespillow.net, is stating the actual limitation rather than being cautious.
What to Do Instead
The cover comes off and goes in the machine. That is the whole design: a washable layer over an unwashable core.
For the foam itself: air it. An hour or two out of its cover, somewhere with moving air and out of direct sunlight, once a month.
Spot cleaning only, with a barely damp cloth and a very small amount of mild detergent, blotting rather than soaking, then air-dried completely before the cover goes back on.
Sunlight Is Not the Answer Either
Ultraviolet light degrades polyurethane, making it yellow, brittle and crumbly.
Airing in shade with a breeze is right. A day on a washing line in summer sun is not.
A Protector Solves the Problem
The practical answer, and the cheapest.
A zipped protector under the pillowcase takes the sweat, oils and skin cells that would otherwise reach the foam. It washes; the pillow does not need to.
It costs a fraction of a pillow and it is what determines how long one stays pleasant.
If It Has Been Soaked
Press out as much water as possible without wringing, which tears it, then air it for as long as it takes.
Any lingering smell means moisture remains, and the pillow should be replaced.
Wash the Cover Regularly
Monthly, with the bedding.
Air It Between Washes
An hour uncovered makes a noticeable difference.