Naphtha or mineral spirits will do a great job cleaning a shellac finish- a little on an old t-shirt will do, but mind the warnings on the can!
Also, test a little inconspicuous spot before proceding, just to make sure that it really is shellac.
Originally Posted by Jason Sypher
No. No. No. The fastest way to make sure you'll never be a good musician is to take shortcuts...don't cheat yourself out of all the rewards of music by trying to invent a better crutch....