Before applying new coats of paint to the outer surface, it must be thoroughly cleaned. Ensure that all dirt, dust, mildew, and other pollutants are thoroughly cleaned and removed when washing the outside walls.

To prepare the surface for the application of new paint. When cleaning corners, behind doors and windows, beneath cornices, and in grooves where dirt and mildew might hide, clean the loose dust and cobwebs first with a duster, brush, or dry cloth, then thoroughly with water and detergent. For cleaning external surfaces, use pressure washers or constant sprays of water.