We have some kind of lichen or mold on the plastic siding on one side of the house. What's the best way to clean it off?
Spring Cleaning? An effective way to clean mold & mildew off aluminum or vinyl siding! After a lot of researching the web for various methods, I simply used one scoop of Oxy-Clean and a cap full of laundry detergent in about 2 gallons of warm water. The soft bristle brush, about 4 ft. long, is the kind used for applying roofing cement, etc.
Just spray rinse, wash with soapy water and rinse again. Works great!
Rent a pressure washer at Home Depot for the day.
I'd be more concerned with what's allowing it to grow in the first place.
Tilex or bleach will probably do it, but test it on a small piece to make sure it doesn't affect the color of siding.