Howdy folks. I don't get to spend nearly as much time here as I would like. I have a few old vintage Gerber fixed blades with original (Do you call them "shrink-fit"?) sheaths. I am talking about sheaths that are in great condition, with original finish, that are around 30 years old. The problem is that they have become loose fitting to the knife. I even have one that will spill the knife when turned upside-down. Is there a way to shrink this type of sheath so that it will again grip the knife? I would hate to damage the leather in any way, of course. Thanks a bunch for any advice!