Fresh Paint: Time Is of the Essence
Time is everything in successfully removing paint from grout. When paint sits on the grout, it is absorbed. You will need a wet cloth, and you should try to wipe it up as soon as the spill occurs. If you are using latex paint, you can use water and soap. Be sure to use quick wiping motions because you do not want to rub the spill and press the paint into the grout.
If you are using oil-based paint, you will need to use mineral spirits to remove it. If you aren’t able to do this quickly enough, you will have permanent damage that needs another solution.
If paint spilled on your grout and had a chance to dry, you will need to use a different method to remove it. You will start with a solvent. You can buy one at a paint store, or you can make a solution at home with rubbing alcohol and water. If the stone on the floor is natural stone, you should test a small area before you start to make sure that it won’t be damaged.
Rubbing Alcohol Solvent: You can dip the end of a cloth in the rubbing alcohol and blot the paint. After you blot it, you can gently rub it until the paint lifts off. Do not pour the rubbing alcohol directly on the grout; be sure to put it on the end of the cloth and use the cloth to remove the paint.
Commercial Solvent: If you buy latex paint remover from a store, you should still test a part of the natural stone. Commercial solvents may be harsher than rubbing alcohol, so you will want to use the same process. Dip the end of the cloth in the solvent, and blot the paint. Then, you can wipe it away until the paint is removed.
Mineral Spirits: If you have spilled oil-based paint, you can try mineral spirits. If they don’t do the trick, you may need to try acetone or lacquer thinner.
Use a Battery Powered Toothbrush for Difficult Stains
If you use a cloth with the solvent and there is still paint there, you can take a battery-operated toothbrush, dip it in the solvent, and use it to scrub the paint free. Don’t press down; scrub the paint side to side to lift it. This method will work well with latex paint or with mineral spirits for removing oil-based paints, but if you use harsher solvents such as acetone, the solvent may dissolve the bristles of the toothbrush.