To wash walls before painting, vacuum up dirty areas and use a cleaning solution consisting of trisodium phosphate. TSP is highly recommended by painting professionals for cleaning surfaces prior to painting.
- Prepare the wall for washing
Vacuum up dirty areas on or adhering to the wall, such as cobwebs or clumps of dust.
- Wash the wall
Mix TSP powder with warm water. Use eye protection and gloves to apply the TSP solution. Using a cloth, wipe down the walls with the TSP solution. Rinse surfaces with a damp, clean sponge. As TSP can darken some types of wood, use on wood only if desired.
- Let the wall dry
Wait for the wall to dry thoroughly before beginning painting.