Remove multiple layers of paint from a wall with a chemical paint remover or stripper. The two types of paint removers include liquid and paste. Liquid paint removers remove one or two layers of paint. Paste removers remove up to 10 layers of paint with one application. Once you paint the remover onto the wall, you leave it alone to do its job then scrape it and the layers of paint away.
Pour a portion of the paint remover from its original container into a separate smaller container with a mouth wide enough to accommodate your brush. Dipping your used brush into the primary container may taint the supply.
Brush the paint remover thickly in one direction over 1 square foot of the wall; the idea is to work with an area small enough to treat in its entirety before the paint remover dries. Brush in one direction. Do not reapply paint remover to areas that have already been covered.
Leave the paint thinner on the wall for the manufacturer-recommended amount of time, which is usually around 30 minutes.
Test to see if the paint thinner has done its job. Use your putty knife to scrape the paint using a circular motion. If you get through to the wall beneath the paint, the thinner has done its job. If the paint remover has not done its job, leave it to work for another 10 minutes. Remove the bulk of the paint in that section with your paint scraper using long horizontal or vertical strokes.
Wipe away any paint residue left behind by the scraper. Use a rag or scouring pad moistened with paint remover.
Clean any residual paint thinner from the wall. Some paint thinners can be rinsed away with water. Others require ethanol or white spirit. Consult the paint thinner's manufacturer instructions for specific details.
Wear chemical-resistant rubber gloves and a face mask whenever handling paint remover. If you are removing paint from an interior wall, make sure that the paint remover is listed as safe to use indoors with adequate ventilation. Lay plastic sheeting beneath the spot you are working to catch any falling paint or dripping remover. Certain types of paint are harder to remove than others. In some cases, you may have to apply a second layer of paint remover to completely remove the paint.