to dehydrate i soak my skins in a solution of water, borax and salt for about 2 days, mixing a few times a day.
then roll the snake skin up from head to tail and soak everything in a 50/50 mix of alcohol ( isopropyl ) and glycerin. leave the tail out of this solution, and every day knead it a little bit. takes about 5 days or so, longer or shorter dont seem to matter much either. stretch it out on a piece of plywood with thumbtacks or trapper tacks and let dry. should be soft, pliable, and will keep forever.
-Treekiller