Things You'll Need
TSP (Tri-sodium Phosphate)
Invisible (colorless) spray paint
A dry non-abrasive scrubber
Soft wash cloths
Waterproof interior/exterior enamel paint
A soft brush or a sponge to spread the solution on the wall
Paint plaster walls with waterproof interior/exterior enamel paint. This will keep your plaster wall clean from dust and dirt and save time on future cleaning. Explore imaginative options to decorate your plaster wall. You can use Plaster of Paris (PoP) or wallpaper, depending on the location of your plaster wall.
Identify the type of wall. The above steps work only for plaster walls. However, dry walls, which look the same as plaster walls, have a thin paper coating with a gypsum base that is soluble on application of water. Make sure you are cleaning a genuine plaster wall. Avoid using a vacuum cleaner or air blower. Instead use a damp sponge after you are done cleaning and spraying the plaster wall. This will remove any loose particles from the surface.
How to Clean Plaster Walls. If your home or office interiors have plaster walls, consider cleaning them regularly as they tend to get dirty more often than painted walls. Plaster walls absorb moisture faster than painted walls and are more likely to attract dust and stains. The porous surface of plaster walls requires constant attention and cleaning.
Scrub the wall surface with a brush or damp cloth to ensure that the wall has an even finish. Plaster walls tend to be a little uneven on the surface, which makes them difficult to clean.
Use a strong solution of TSP (Tri-sodium Phosphate) mixed with water with a ratio of 1:15 (TSP: Water). You can also try using a non-phosphate substitute for water.
Use a dry non-abrasive scrubber, a soft brush or a sponge to rub the solution on the area of the wall which requires cleaning. The water will be absorbed by the wall surface but the Tri-sodium Phosphate action will disintegrate dirt and stains.
Allow the cleaned area to dry for few hours. Use a mild solution of TSP and scrub the surface again with a soft cloth to remove loose dirt off the wall. Do not scrape off or you will end up spoiling the wall surface.
Use an invisible (colorless) spray paint to fill out the porous surface of the wall to keep the wall surface clean.