Cleaning

How do I wash vinyl siding by hand?
Wash vinyl siding with a soft cloth or ordinary long-handled, soft bristle brush. For textured surfaces, use only a soft bristle brush to keep the grooves in the texture stain-free. For best results, start at the bottom of the house and work up and rinse the cleaning solution completely before it dries. If your house has brick facing, cover the brick so that it is not affected by the runoff.

Can I use a power washer to do larger area's or the whole house?
Yes, though you should read the washer instructions carefully before use. When cleaning, hold the power washer straight at a flush level with the siding to keep the water on top of the siding where it can clean most effectively, Use extension wands or work off ladders at levels above ground height. Do not aim the power washer upward as water may be driven behind the siding. Power washers above 3200psi can damage siding.

You should also follow the siding manufacturer’s recommendations.  There are manufacturers that don't want pressure washers used on their products at all.  Others allow them, but have limitations on the amount of pressure and the cleaners that can be used.  Most will caution against the use of pressure washers around any opening in the wall, such as windows, doors, electrical wiring, and plumbing.

How do I remove mold and mildew?
Small spots of mold and mildew can be handled with commercial bio-degradable siding cleaners and other cleaners such as Fantastik^® or Windex^®. For larger sections, a solution of vinegar (30%) and water (70%) has proven successful. Alternatively, you also could try the following solution: 1/3 cup (2 2/3 ounces) powdered laundry detergent (e.g., Tide^®, Fab^®, or equivalent), 2/3 cup (5 1/3 ounces) powdered household cleaner (e.g., Spic & Span^®, Soilax^®, or equivalent), 1 quart (32 fluid ounces) liquid laundry bleach, and 1 gallon (128 fluid ounces) of water.

What types of cleaners should I use for other stains?
A list of commonly accepted cleaners is provided in the box below. Be sure to spot check any general or stain specific cleaner before using it on a large section of siding. After removing the stain, rinse thoroughly with water. Do not use cleaners containing organic solvents, undiluted chlorine bleach, liquid grease remover, nail polish remover, or furniture polish or cleaners. They can affect the surface of the siding. 
Brown stains near ground levels are often due to mud splashing up on siding. Mulch or ground cover can help minimize this problem. Sprinkler systems that shower vinyl with water high in iron content can stain siding brown. A cleaner containing iron/rust remover can be used. Mold/mildew tend to produce black stains. Vinyl siding cleaners containing oxidizing bleach and tend to be effective.
Artillery fungus grows in decaying mulch. Thus, the importance of removing and refreshing mulch. When fungus becomes ripe in spring and fall, it can pop up as much as 20 feet above ground level and attach to vinyl siding. The down side is that it is very difficult to remove from siding. It sticks like super glue. If successful scraping off artillery fungus, brown stains remain. There is no cleaner that will successfully remove artillery fungus without damage to vinyl.