Perspiration stains on silk are tricky to remove. Some silk blouses will grab hold of a dot of sweat and spread it like a virus. Not pretty. If you're going to wear sillk on a hot day, try wearing shields beneath your blouse. If it's too late for that (and I can relate), do what Madonna does and spray Vodka on the stains. How I love a double-duty cure. Good luck with your fashion dilemmas.