How do you wash a silk pillowcase?

• Machine wash, delicate or silk cycle, 30 °C maximum, in a laundry bag.
• Reduced spin, 600 rpm maximum.
• A mild detergent, free of enzymes and bleaching agents. No fabric softener.
• Air dry, flat or on a hanger, never in a tumble dryer, never in direct sunlight.
• Wash every one to two weeks, like the rest of your bed linen.

The rest of this article explains the reason behind each rule. That is what will let you decide for yourself the day you face an ambiguous care label or an unfamiliar bottle of detergent.

Cotton is a plant fibre: cellulose. Mulberry silk is a protein fibre, made of fibroin — a protein, like the one in your hair or your nails.

That single difference explains everything else:

• The enzymes in modern detergents digest proteins. That is precisely their job: to dissolve organic stains. A protease cannot tell the difference between an egg stain and your pillowcase. With every wash, it eats away at the fibre a little.
• Silk does not like alkaline conditions. Standard detergents are alkaline, which dulls silk and makes it rough over time. A pH-neutral or slightly acidic detergent preserves the hand of the fabric.
• Heat and mechanical friction wear it out. A drum spinning at 1,200 rpm with a pair of jeans next to it is pure abrasion.

One more useful point: the denser the silk, the better it withstands washing. That is what momme measures. A 22 momme silk is considerably more robust in the wash than a 16 or 19 momme silk, which remains common at entry level.

1. Close the flap or the fastening and slide the pillowcase into a laundry bag. The bag is not a detail: it stops the silk from wrapping around another textile or catching on a zip.
2. Wash it with light items of the same colour — another silk piece, fine lingerie. Never with jeans, towelling or anything carrying hooks, Velcro or metal buttons.
3. Choose the silk, wool or delicate cycle, at 30 °C. If your machine will not go lower, cold water works perfectly well: silk does not need heat to come clean.
4. Reduce the spin to 600 rpm maximum. This is the setting most people forget, and it is the one that creases silk the most.
5. Use half the usual dose of detergent. A pillowcase weighs a few dozen grams. Overdosing leaves a film that dulls the fabric.

Allow about an hour for a delicate cycle. Take the pillowcase out as soon as the programme ends: left damp and bunched up in the drum, it sets creases that are hard to remove.

If your machine has no suitable cycle, or if the pillowcase is pale and you would rather keep an eye on it:

• Fill a basin or the sink with lukewarm water, 30 °C, the temperature of a baby's bath.
• Dilute a small dose of mild detergent before putting the pillowcase in.
• Let it soak for three to five minutes, no longer. Squeeze gently, like a sponge.
• Never wring silk, and never rub it against itself. The fibres break and it shows in the light.
• Rinse in clear, cold water until no foam is left.
• Lay the pillowcase flat on a dry towel, roll the towel up and press. Most of the water comes out that way.

You do not need a luxury product. Turn the bottle around and read the composition. What you are looking for:

• The words “for silk”, “wool and silk” or “enzyme-free”.
• Neutral pH.
• No bleach and no optical brightener, which yellow ivory silk over time.

What to avoid entirely: all-in-one detergents and capsules, which almost always contain enzymes; pre-wash stain removers; and fabric softener, which is pointless here — silk is already soft, and softener leaves a greasy film that makes it dull and less slippery.

One stopgap alternative: a mild, silicone-free shampoo, heavily diluted. Silk and hair are chemically close, which makes this less odd than it sounds.

No tumble dryer. Not on the delicate cycle, not on cool air, not “just for ten minutes”. Heat combined with tumbling shrinks silk and destroys its sheen irreversibly.

Hang the pillowcase on a hanger or lay it flat, in the shade, indoors, away from a radiator. Direct sunlight fades silk faster than any wash — that goes for dark shades as much as for ivory.

The good news: silk dries quickly. Allow two to four hours depending on the room. Washed in the evening, your pillowcase is back on the pillow the next morning.

In most cases, no. A 22 momme pillowcase dried on a hanger falls back into shape on its own. If you want a perfectly smooth finish:

• Iron it while still slightly damp, inside out.
• Iron on the silk setting, the lowest one, without steam — droplets leave water marks.
• Place a thin cotton cloth in between if your iron runs hot or its soleplate is old.

A garment steamer also works, held at a distance, without resting the head on the fabric.

Once a week, twice at most. A pillowcase collects sebum every night, along with traces of night creams, moisturiser and hair serum. It is the textile in your home that spends the most time against your face.

Lean towards once a week if you apply skincare in the evening, if your hair is oily at the roots, or if you exercise at the end of the day. The rhythm of the rest of your bed linen remains a good guide.

This is also the most down-to-earth argument for owning a second pillowcase: one on the pillow, one in the wash, and you never sleep on cotton while the first one dries.

• Fabric softener — leaves a film, kills the glide.
• The tumble dryer — shrinkage and loss of sheen.
• Bleach and whitening detergents — attack the protein directly.
• Wringing to remove water — breaks the fibres and leaves white creases.
• Long soaking — beyond a few minutes the water adds nothing, and hot water dulls the fabric.
• Washing with heavy laundry — mechanical abrasion.
• Perfume and hairspray sprayed onto the pillow — alcohol marks silk.

Foundation, mascara, hair oil, night cream: all of it comes out if you act quickly.

Dab the stain with cold water and a clean cloth, working from the edge towards the centre, without rubbing. For anything greasy, use a drop of diluted mild detergent applied with a fingertip, then rinse with clear water. Then wash the pillowcase as usual. Never let a greasy stain dry: it oxidises and becomes far harder to remove.

Does a silk pillowcase shrink in the wash?

In cold water or at 30 °C, no, or negligibly so. Shrinkage comes from heat: hot water, tumble dryer, an iron that is too hot.

Can it be washed with the rest of the bed linen?

No. Sheets and duvet covers go in at 40 or 60 °C with an enzyme detergent — precisely the two conditions to avoid with silk.

Does white vinegar really work?

A tablespoon in the rinse water neutralises detergent residue and revives the sheen. Rinse with clear water afterwards. It is an occasional step, not a routine for every wash.

How long does a well-cared-for silk pillowcase last?

Several years of regular use. Polyester satin, by contrast, ends up pilling and losing its glide: that is the difference you pay for at purchase.

How can you tell real silk before washing it?

The label should state 100% mulberry silk and a momme count. “Silk satin” describes a weave, not a material: it is very often polyester, which washes at 40 °C with no precautions — and does not glide in the same way.

A silk pillowcase does not ask for special attention, it asks for different habits: cold rather than hot, gentle rather than powerful, open air rather than machine. Three habits to learn once, and the pillowcase lasts for years.

If your question is about the material rather than the care, weight, dimensions and composition are on the product page for our 22 momme mulberry silk pillowcase.