Squirrel tails are very easy. You can de-bone them or leave the bone it, it wont make much difference. Either way, remove as much flesh as possible from around the base of the tail. Then slit the tail up about an inch and give all the fleshy areas a very good dose of 20 Mule Team Borax. Rub it in a bit and sprikle some more on the flesh. Now place them in a cool dry place for about a month to dry out. If you want to gather the body fur from a squirrel for dubbing (great dubbing by the way), simply pluck the fur from the body. Grasp a small tuft of fur and give it a sharp tug towards the head. You'll be surprized how easily it comes out. I have pluck a squirrel in about 10 minutes and not have to bother with all the work and mess of skinning, scraping and drying the pelt.
If you want to "harvest" other volunteer critters like oppossum, then be prepared to skin them, tack them to a board, (flesh side up) and scrape off all the fat and connective tissue that you can. Use a dull knife and scrape sideways to remove the flesh. Now, rub in a generous amount of 20 Mule Team Borax and set the pelt in a cool dry place to cure for about a month. You should check every few days to make sure it's drying out properly and that no critters are getting after it.
No matter what you collect for the wild, feathers, fur, tails, pelts etc. NEVER mix it in with your tying supplys right away. Place it in its own zip lock bag with some moth balls or a piece of flea collar to kill off critters that may still be there or have hatched from eggs or larva on the pelt. It ain't rocket science but it get a bit messy sometimes. If you ever try to skin a beaver you'll quickly understand what I mean. Good luck and I hope information this helps a bit.
Jim Smith