Labeling on cans of polyurethane and lacquer can sometimes be confusing. It may not be obvious whether the finish is solvent-based or water-based. One way to distinguish which is which is to read the label for the thinning and clean-up solvent. Solvent-based products will list a solvent such as petroleum distillate, aliphatic hydrocarbon or lacquer thinner. Water-based products will list water. Another way to tell is to open the can and look at the finish. Solvent-based products will be clear; water-based finishes will be white. The whiteness disappears when the finish dries.