Vinyl siding usually cleans up easily with nothing more than soap and water, and a yearly scrubbing will keep it looking new. For basic cleaning, use general-purpose cleaner mixed with warm water. Apply it with a soft-bristle cleaning brush, scrubbing the full length of each lap (Photo 1). Start at the bottom to avoid streaking, and use your garden hose to rinse off each section before it dries.
For tough spots like paint drips, tar, and pencil and pen marks, use a nonabrasive bathtub cleaner or nylon scrub pad (Photo 2). Use ammonia cleaners or a solution of 1 part bleach in 4 parts water to clean mold and mildew stains. (However, never mix ammonia and bleach.) Rinse thoroughly while the siding is still wet.
Don't use paint thinner, nail polish remover, spot removers, paint remover, straight chlorine bleach or furniture cleaner on vinyl. These types of cleaners can damage the surface of the siding.