Squirrel tails after you cut them off, personnally I would wash them with dawn and then a little hair conditioner. Once they're cured up it's much nicer tying with them. Coon tails, I'd rather buy an artic fox tail then deal with any problems from raccoons.

I never boned out squirrel tails before but got several in a swap box and they are MUCH better to tie with when they split out.