Silk is a natural fiber made by the silk worm. It is strong and easy to dye, but it is also difficult to maintain, as it fades easily. Rayon is made out of wood pulp, and, in some forms, can closely resemble silk. Sometimes, if a silk or rayon garment gets wet and dries improperly, the water leaves a stain on the fabric. Rewetting the fabric will get rid of the stain in most cases.
Lay the silk or rayon garment with the water stain out flat on an ironing board.
Dampen a towel and dab the water stain to get it slightly wet.
Turn the iron on its lowest setting and gently touch the fabric with it to dry the stain. Turn the fabric over and repeat the process on the other side. Once the fabric is dry, the stain will be gone.