To clean interior surfaces for painting:
EXPERT TIP: Clean surfaces in homes that house or previously housed smokers particularly well.
[ 1 ] Purchase a box of trisodium phosphate (TSP) from a hardware or paint store and follow mixing directions on the package. Typical mixing ratio is 1/4 to 1/2 cup of TSP per gallon of water for medium- to heavy-duty cleaning projects. Alternatively, there are other less caustic (and less effective) surface cleaners available at hardware stores.
CAUTION: Trisodium phosphate is a strong cleaner that can injure eyes and unprotected skin. Wear cleaning gloves and eye protection when using TSP. If skin comes in contact with TSP, immediately wash it with water. Do not use TSP on metals or plumbing fixtures. Once the surface is cleaned, TSP must be rinsed from any surface. TSP is not available in all areas.
[ 2 ] Apply the cleaner to the surface following manufacturer’s instructions. Typically, use a clean cloth or sponge that has been dipped in the cleaner and wrung out. Excessive moisture can damage unprotected drywall.
[ 3 ] Rinse the surface to remove any residual cleaner. Use a clean cloth or sponge dipped in clean water and wrung out.
[ 4 ] Allow the surface to dry thoroughly before applying primer or paint.
