I prep plastic coverings with acetone thinned nitrate dope. It sticks to everything, and everything sticks to it, and it does a dandy job of encapsulating microscopic balsa dust from prior sanding operations.

The only thing that sticks to exposed dust is ummm...more dust.

The nitrate dope is also an effective wood hardener. I use it a lot during ARF repairs for other people when the original plane's wood selection was dubious.