Silk bedding should be hand-washed using cool water mixed with mild liquid detergent. Hot water should never touch silk because it will cause the fabric to shrink and wrinkle. Ensure you're not rubbing the fabric together too much, and don't leave it to sit in the water.
Always dry silk bedding on a flat surface in direct sunlight to ensure that the fabric is completely dried out. Because silk is so delicate, it is essential to follow all recommended care instructions so you can preserve its natural beauty. Silk sheets are more prone than other fabrics to shrinkage if they are not dried thoroughly after washing.
You should wash silk bedding as little as possible, and then only when necessary. Remember that silk fabric gets softer with each wash, so the piece will become more delicate over time. For that reason, always hand-wash at first, and then if you need to machine wash, make sure it's on a hand-wash mode (if it has one).