What CellisVallen said. I did a full-mask sculpt and probably went through a big can of the compressed air on it. I recommend blasting small sections at a time.
As far as texturing small pieces, one thing I've had luck with is making "stamps" out of oven-hardening clay (Super Sculpey II for example). Sculpt the pattern you want into the super sculpy, make a little 'handle' for the stamp, bake and then go to town on your sculpt. I've found it really useful for skin texturing