I agree that Borax has been used for years, but as Tumabuck stated, it is not a preservative. It does aid in drying and helps keep bugs out though. I also agree that the claws should be as clean as possible, with all meat and fat off of them, then put in Borax and left out in the air to dry.Anything left in a closed zip-loc bag will retain moisture, and rot. The claws will not dry up unless they are left out where they can get air to them.