30 SECONDS® 64SAWA Spray & Walk Away Surface Cleaner w/ Hose End Sprayer, 64 Oz30 SECONDS Spray & Walk Away kills lichen, moss and algae. It cleans over time. Mother Nature does the work for you. No pressure washing, rinsing, scrubbing, or hosing required. Simply wet and forget. Results become visible over time. Works on many outdoor surfaces like roofs, sealed concrete, asphalt driveways, just to name a few. Bleach and phosphate free, with a neutral pH. Perfect to use in the fall, so it can clean for you, over the winter. Size: