While go for washing, there is still some detergent unexpected on your silk comforters. Although many people reach for Biz or Oxi-Clean when they have a stain on something, do not use either of those products on silk. They will damage them.
So will bleach – it will turn your silk an ugly yellow color.
If you do not want to take any chances with stain removal on your silk sheets, take them to your local cleaner and ask if they can remove the stain for you. Or contact the manufacturer of the sheets for tips and help.
If there there is no need to use any chemical detergent, try to stay away from them for both your silk duvets and your health.