How to Wash a Pillow, Fill by Fill

Updated: September 22, 2026

What is inside the pillow decides whether it can go in the machine.

How do you wash a pillow? Find out what is in it first, because the cover tells you almost nothing. Two pillows can wear the same cotton shell and want opposite things from a machine, since the material inside behaves differently in water.

Most care advice skips that step and goes straight to warm water, gentle cycle, two at a time, low heat. That is written for a polyester pillow, which is what most American beds hold. Run a wool or kapok pillow through it and the pillow is finished in forty minutes, so read the label first, and if the label is gone, open the zipper and look.

How we checked

The washing and replacement intervals come from the Sleep Foundation and from DOWNLITE Bedding, a down and feather maker, both read on 22 September 2026. The temperature and fiber figures come from three peer reviewed papers, linked where they are used, and our own care rules come from our product pages and care cards. We ran no laboratory tests to write this.

Photo: Circadian

Synthetic and down pillows wash, and most people own one.

Can you put pillows in the washing machine? If they are polyester or down, yes, and those two fill most of the pillows sold in America.

Wash two at a time, on opposite sides of the drum. One pillow rides up on the paddles and the machine bangs itself sideways all cycle. Two balance each other.

Use warm water, a gentle cycle, and half the detergent you would use on clothes. Soap that does not rinse out stiffens the material and holds grit against it. Add a second rinse if your machine offers one, because down holds soap deep in the clusters.

A top loader with a center post is the hard case. The post pins the pillow and the agitator scrubs it against itself, which is how a synthetic pillow ends up lumpy after one wash. Use the gentlest setting you have.

Skip the bleach and the cotton against your face stays soft for years instead of going scratchy in a season. A 2023 study in Scientific Reports ran cotton bed linen through 100 industrial washes at 60 degrees Celsius, about 140F, for a 14% loss of lengthwise strength. Ten washes with chlorine bleach dropped the molecular chain length by more than 80%, and chain length is where a fiber's strength lives.

Water is what ruins a natural material, and each one fails its own way.

Every natural material shares one problem with water, which goes in fast and comes out slowly, because the material sits several inches deep inside a sewn cover. A sheet is done in an hour, a soaked pillow holds water for days. What the water does on the way through changes with the material, so here is each one.

Organic cotton clumps, so wash the cover and open the zipper.

People assume cotton washes because their sheets do. The cotton inside a pillow is packed dense rather than woven flat, and water pulls those loose fibers into hard knots that shaking never undoes. Take the cover off through the zipper and wash it cold with a mild detergent.

If the cotton itself needs refreshing, lay it in indirect sunlight for a few hours and it opens back up. The Circadian Organic Cotton Pillow ($179) is certified organic through every layer under the Global Organic Textile Standard, GOTS, which covers a finished textile rather than the raw fiber alone. Wash that cover as often as you like.

The cover washes, the cotton stays

Organic Cotton Pillow

The cleanest air in your home is right above this pillow. The cotton goes in unbleached and unfinished, with no wrinkle-resist resin to off-gas formaldehyde at your face. Cotton is all it is. Certified organic through every layer, license GOTS-10229 from Oregon Tilth, and the zipper on the short end sets the height on night one.

Shop the Organic Cotton Pillow

Handmade in New Jersey · Free shipping

Organic wool felts, and felting cannot be undone.

Wool fiber is covered in microscopic scales. Put those scales in hot water, move them around, and they hook into each other and lock. That is felting, which is how hat makers turn a fleece into a solid brim, and it is what a washing machine does to a wool pillow in one cycle. It comes out a dense mat, half its old size, and no amount of teasing opens it back up.

So the wool stays out of the machine. Take the cover off and wash it in cool water with a gentle detergent. Air the wool itself in indirect sunlight and it opens back up on its own.

Wool also asks for less washing than anything else in the bed, because it moves moisture off your skin and into the fiber while the surface stays cool. The Circadian Organic Wool Pillow ($209) is certified organic through every layer, and the wool does that untreated, so there is no finish to off-gas and none to wash out.

Photo: Circadian

The one that needs washing least

Organic Wool Pillow

Cool sleep, and hypoallergenic without a single thing applied to the wool. Wool moves moisture off your skin and holds it, up to 30% of its own weight, while the surface stays cool. Dust mites need humidity above roughly half to survive, and the air at your face never gets there. Certified organic through every layer, GOTS-10229 from Oregon Tilth.

Shop the Organic Wool Pillow

Handmade in New Jersey · Free shipping

Kapok collapses, and it does not come back.

Kapok is the lightest natural fiber on Earth, because each strand is a hollow tube of air with a wall a micron or two thick. Soak it and those tubes crush flat. The fiber mats into dense clumps, and the lightness you paid for is gone for good.

Prevention is the whole job here, since no treatment brings it back. Wash the cover, keep a protector on the Wild-Harvested Kapok Pillow ($119), and spot clean a mark with a barely wet cloth and a drop of mild detergent. Dab rather than scrub, and let it dry through before bed.

Latex tears in a machine, and sunlight is the other thing to avoid.

Latex is springy and it hates being wrung. A washing machine pulls shredded latex apart, and once the pieces tear the bounce is finished. Hand washing is no better, because latex holds water in its open cells and dries too slowly.

Wash the cover, then lift the latex pieces out and lay them in a shaded, airy spot for a few hours. Keep them out of direct sun, because ultraviolet light yellows latex and breaks it down. The Tree-Tapped Latex Pillow ($169) uses latex tested to OEKO-TEX Standard 100 at Class 1, the strictest tier, the one written for products made for babies.

Buckwheat hulls must never get wet, and the sun does the rest.

Buckwheat carries the strictest rule in the category. Water breaks down the cell structure of a hull, and wet hulls inside a sewn cover dry far too slowly to be safe, so mold follows.

Empty the hulls into a dry container, wash the cover cold, and spread the hulls in direct sunlight. Direct sun is right here and nowhere else in this guide. When the hulls lose their edge after a few years, fresh hulls start at $59, so a Buckwheat Pillow ($149) carries on instead of going in the trash. Our guide to cleaning a buckwheat pillow walks the routine, the schedule, and what to do the moment something spills.

Buckwool has two chambers, so it has two answers.

The Buckwool Hybrid Pillow holds buckwheat on one side and organic wool on the other, with an organic cotton divider between them and one zipper that reaches both chambers, and you flip it depending on the night. Wash the cover, sun the hulls from the buckwheat chamber, and air the wool from the other in indirect light, never in direct sun and never in water. The buckwheat side takes fresh hulls from the same $59 bag.

The cover and the protector do the hygiene work.

Skin oil, sweat, loose skin cells and whatever went on your face before bed are what collect in a pillow. Almost all of it stops in the first two layers, which is what makes every rule above workable. Core body temperature falls at night as part of the circadian cycle, and bedding that traps heat works against that fall, so the layers nearest your face take the difference.

Start with the cover, because it is the one piece doing real work that a machine can take. Unzip it, lift the material out, and wash the cover cold on a gentle cycle with a mild detergent. Pull it back into shape while it is still wet, then let it air dry on a rack. Keep it out of the dryer, and low heat is no exception, because heat shrinks the fabric a little every cycle and a cover that has shrunk will not go back over the pillow it was cut for.

A zippered protector does the most work of anything you can buy for a pillow you cannot wash, because it seals the material inside and takes whatever comes through the case. The Circadian Waterproof Organic Cotton Pillow Protector ($79) is waterproof, certified organic as a finished product, and washable as often as you want. Run it cold and hang it up to air dry, and keep bleach out of that load, because chlorine attacks the waterproof film and a protector that has lost it is only a second pillowcase.

Cotton protectors do not cost you airflow. The Sleep Foundation finds cotton-based protectors keep good airflow and stay cool, while polyester, microfiber and PVC hold noticeably more heat against your face all night. Put a pillowcase over the top and the material inside stays clean for years without meeting water.

Drying is where most pillows are lost.

Two things go wrong in a dryer, and heat is the first. High heat leaves fiber brittle, and a brittle fiber snaps instead of bending the next time your head lands on it. That gray mat on the lint screen used to be inside your bedding. A 2022 study in PLOS One measured a vented household dryer and found it put microfibers into the air at about 81% of the amount the same wash sent down the drain.

Stopping early is the second. Water hides in the core of a pillow long after the outside stops feeling wet, and mold in the middle of a pillow is not something you clean out afterward. Squeeze the middle before you call it done.

Dryer balls beat tennis balls. Wool balls knock the material apart without adding heat, and they leave behind none of the rubber and dye a tennis ball does. Three in a big drum are enough. Our guide to drying and fluffing a pillow without ruining what is inside covers the hand technique and the no-dryer method.

How often each piece comes off the bed.

How often should you wash pillows? Three different numbers, because three different things are in play.

The pillowcase goes twice a week. Your face is on it for about a third of your life, and facial skin is the oiliest you own, so moisturizer, hair oil and sunscreen all end up in the weave. Our guide to how often to wash sheets gives the case its own schedule.

The protector goes monthly, and right away after a spill. The pillow itself depends on what is inside. A synthetic or down pillow goes in two or three times a year, which is where the Sleep Foundation puts most people, and a natural pillow never goes in at all.

Washing is what takes the height out of a pillow.

Every wash costs a pillow a little height. Water swells the fiber, tumbling packs it tighter, and it leaves the dryer slightly denser than it went in. Do that four times a year and the laundry ages the pillow faster than your head does, which is the whole case for a protector: a pillow washed once a year outlives the same pillow washed every season.

When a natural pillow does settle, the answer is material rather than laundry. Every Circadian pillow opens at a zipper on the short end. Add organic cotton or organic wool back through it and the height returns, which a wash was never going to do.

Look at the gap in that last row. A pillow you can only wash is a pillow you throw away, and most synthetic-fill pillows need replacing every 6 to 18 months. A pillow you can open and feed is one you keep.

Three situations change the answer.

When does this stop being the right routine? In three places, and a diagnosed dust mite allergy is the first. A 1992 study in the Journal of Allergy and Clinical Immunology found no dust mite came through water at 55 degrees Celsius, about 131F, and below that the mites lived. A cold wash still took out more than 90% of the mite allergen, the protein a reaction is aimed at. If a doctor has diagnosed you, that routine is a question for them.

A humid house is the second. Above 60% indoor humidity, every natural material takes on moisture faster and needs airing more often, and our guide to the right humidity for sleeping covers where to put the number.

A spill is the third, and speed decides it. Get the cover off and the material out within the hour, spread buckwheat hulls in the sun for two or three days before they go back, and expect soaked kapok to be finished, which is the argument for a protector one more time.

Wash the cover, air the material, keep the pillow.

So how do you wash a pillow? Check what is inside it first. Polyester and down go in two at a time, warm and gentle, then take a long low-heat dry with wool balls. Cotton, wool, kapok, latex and buckwheat never go in. Wash their covers cold and air dry them, the protector monthly, the case twice a week, and air the material inside once a month.

A pillow that comes apart at a zipper changes what washing is for. You are no longer scrubbing to buy six more months out of something headed for the trash, you are keeping a clean surface on a pillow whose material you can top up, air out, or refresh. Every Circadian pillow is filled and sewn by hand in New Jersey, and our organic cotton and organic wool pillows carry Global Organic Textile Standard certification under license GOTS-10229 through Oregon Tilth, set out on the certifications page. Ask me for the certificate and I will send it.

A pattern Circadian sees in customer conversations

The letters about washing are almost never about washing. Someone writes because a pillow went flat and wants to know whether a wash will bring it back. It will not, and it does not have to. One reader had washed a cotton pillow twice a year for three years chasing the height, and was flattening it further each time. What she needed was a few handfuls of cotton through the zipper. If you are standing over the machine wondering, describe the pillow to me first.

Still choosing the pillow itself?

If the pillow you are washing is one you never really liked, the care routine is the wrong problem to solve. The pillow quiz takes 30 seconds and lands on a material. Read which pillow stays cooler, organic wool or cotton if heat is the reason you are up, or why you get so hot when you sleep for what your body is doing, and start with our bedding for hot sleepers.

Frequently Asked Questions