Following is a basic understanding of the common solvents available in paint stores and home centers.
Mineral spirits (paint thinner) and naphtha dilute and clean up oils and varnishes, including oil-based polyurethane varnish. Neither of these solvents damage any fully dried finish, so you can safely use them for cleaning—that is, removing grease or wax.
Denatured alcohol thins and cleans up shellac. This solvent will damage a dried shellac finish almost instantly and lacquer and water-based finish fairly quickly, so be very careful if you use alcohol for cleaning.
Lacquer thinner and acetone thin and clean up all solvent-based lacquer products. These solvents can damage all wood finishes, so don’t use them for cleaning.
Super lacquer retarder containing butyl cellosolve, also called ethylene glycol mono-butyl ether or “EB,” evaporates very slowly, so it can be used to slow the drying of lacquers, shellac and water-based finishes. But use very little (less than 5%) or the finish may take days to fully dry.
Toluene (tolulol) and xylene (xylol) have very little use in wood finishing, though they can be very effective for cleaning grease from metal.