Yes, usually, but you need to do it gently and follow the care label. Many silk items, including a silk pillowcase, can be washed on a delicate cycle in cool to lukewarm water using a mild detergent without bleach or enzymes.

Use a laundry bag, wash with similar colors, and choose a low spin speed. Hand washing is also an option, especially for very delicate silk or if the label recommends it.

Avoid hot water, wringing, harsh stain removers, and the dryer because these can cause shrinkage, dullness, or damage. Air dry silk flat or hanging, out of direct sunlight. If you are unsure, test a small hidden area first or choose professional cleaning.