How Do You Remove Polyurethane from Marble

Use a little solvent at a time and scrape it up or wipe it up with a cloth as soon as it is soft enough to remove. You could probably also use a heat gun to soften the urethane–but again, wipe it off as soon as you can and use acetone to wipe off any stain that is left.

What will dissolve polyurethane finish?

• Pour equal parts of lacquer thinner and denatured alcohol into a small empty paint can. …
• Apply the mixture onto the polyurethane finish, covering the stained wood. …
• Remove the mix immediately, using #0000 steel wool to wipe away both stripper and polyurethane.

How do you remove old varnish from marble?

Mix small but equal amounts of hydrogen peroxide and detergent together with water until you form a loose paste. Apply the paste to the remaining stain and cover it with your wet rag to prevent it from drying out. Wait about 10 minutes and lift the remaining varnish up by simply pulling up the rag.