Dress in old clothes that won't be ruined if splashed with bleach. Wear protective eye gear, rubber gloves and slip-resistant footwear. Spray plants and shrubs around the perimeter of the house where bleach runoff from the roof might land. Clear the moss-affected asphalt of any objects or large debris.
Combine a solution of bleach water by adding 2 cups bleach to 1 gallon water in a household bucket. Stir the solution with a wooden or plastic spoon.
Pour the solution over moss affected areas of asphalt. Scrub the affected areas with a push broom to loosen moss and spread the bleach solution.
Allow the solution to penetrate the moss for approximately 30 minutes. Spray the entire asphalt area with a water from a high-pressure hose to wash away the bleach solution.
Brush away any remaining moss debris with a push broom. Reapply bleach solution and repeat process if necessary, until moss is eliminated.