I'm sure most of you have seen the reaction of period hanger metal fittings having contact with brocade fabric material. (At least this is what I think is happening). I have coated the contact sufaces with Renwax and this seems to the corrosion somewhat. My question is, is this just the nature of the metal alloy fittings or is it an interaction between the materials? Since I've seen similar powdery degredation on period "zinc" badges I wonder if anything can be done conservation wise. Sorry if this has been previously discussed but a search did not reveal much.