If you have plaster walls, you may think that the walls get dirty far more quickly than any other type of wall inside of a house. Well, you’d probably be right! That is because plaster absorbs moisture, and with it, brings dust and anything else that floats around in the air to stick to the walls.
First, scrub the wall with a brush (it will need to be soft-bristled if there is a texture pattern to the plaster wall) to remove any loose dirt, dust, etc. Then rub it gently with a damp cloth.
Next, clean the walls with a solution of TSP (also known as Tri-Sodium Phosphate). You will need a strong solution, about 1:15 ratio of TSP: Warm Water. Scrub the wall with a brush or sponge, then let sit for several hours to dry. Then using a mild solution of TSP (1:25), scrub the wall again and allow to dry. You may want to use a heater or fan to speed the drying process, especially if the temperature is colder.
Enjoy your nice clean plaster walls!