Cover plants and flowers close to the home with drop cloths. Tape plastic sheeting over exterior electrical outlets.
Mix together a solution of 1 cup of liquid detergent and 1 cup of oxygen bleach in a bucket of warm water.
Pour the mixture into a garden sprayer or pressure washer. Do not use a pressure washer on wood siding.
Spray the moss liberally with the solution. Starting from the bottom up, work in small areas, and rinse with clear water before moving to the next area. If you're using a pressure washer on vinyl siding, start it at a low setting and keep the nozzle moving at all times to avoid denting the siding.
Scrub stubborn areas with a long-handled scrub brush until all the moss is removed. Examine the surface closely, as moss can regrow quickly if there is any left on the surface.