Shop Tip #038
© Frank Ford 2004; Photo by FF

A cotton swab moistened with acetone can instantly detect a nitrocellulose lacquer finish - the barest touch will leave a strong permanent mark in the surface. Catalyze polymer finishes are unaffected by acetone, and a shellac French polished coated surface will show only the barest haze if touched by acetone. So, by this test alone, you can get a good sense of what you're dealing with for finish repairs.