In many cases, this damage is caused by contact with a liquid that contains chemicals which deteriorates silk. The biggest culprit is chloride salts which are found in perspiration, deodorants, foods and skin lotions. When the solution dries, the moisture evaporates out, but the salt residue remains in the fabric and begins to break down the silk. Do NOT rub the stain! Immediate removal after contact is the only remedy, so point out the stain to your dry cleaner and have the garment cleaned immediately.