Clean up your roof with Spray & Forget Revolutionary Roof Cleaner Concentrate. This roof cleaner uses a fast-acting formula to remove stains caused by algae, mold and mildew – delivering results in minutes, not weeks! Packed in a 1-gallon bottle, this concentrate can make up to 10 gallons of cleaning solution – enough to cover 1000 to 2000 square feet. Spray & Forget is an ideal roof cleaner for asphalt shingles, wood shingles, slate shingles, clay shingles and tile shingles.