I know this has been covered before, and I searched the forum but didn't find anything. I have a stain of unknown origin at the bottom of a purple and blue woven silk Burberry tie (please ignore the maker and forgive me, I purchased it before I found SF). It is barely noticeable, only very slightly darker than the tie and I only see it from certain angles. It is much more obvious from farther away. How should I go about removing this stain, preferably with standard household items? Thanks.