How do I determine what kind of finish a wood surface has? I have some cabinets that I want to re-coat with lacquer or urethane but I don't know what was originally applied. I am told that I cannot put a polyurethane finish over a lacquer finish, but I do not know how to tell what is already on there. I don't want to strip the old finish off and re-stain the wood, I just want to spruce them up a little. Any suggestions?