A gripe first. Isnt leaving the name, address, and phone # of your business, comercial advertising? I thought we signed off not to do this when we registered? Anyhow, to my topic. Mammal fat creates its own heat. Combine that with storage in a hot place, and you have a recipe for grease burn. Grease burn weakens skin fiber to the point of distruction, and there is no fixing it. From what I have seen so far, bears, small game, and elk, are at especially high risk. Identifacation of grease burn is easy. The affected area will not pickle,or tan, and will tear, with slight pressure. It can often be confused with under-neutralisation, on a tanned skin, and blamed on acid rot. Bottom line, if you leave fat on a skin, store in a cool place.