Hand wash your piece of silk in lukewarm water very quickly. Use Marseille soap. Wring it out by wrapping it in a dry towel. Dry flat, avoiding direct exposure to the sun (temperature too extreme). Iron with an iron set to a temperature between 120 and 130 ° C, with a cloth between the silk and the iron or a good Teflon sole.
And if you have any doubts, the easiest way is to take it to the laundry for a dry wash, where professionals will take care of your item.