Krud Kutter Hose End Multi-Purpose House Wash Cleaner Liquid Concentrate-HW32H4 Quart: Contains Sporex which is a unique additive that removes tough stains from mold mildew algae fungus and moss. The special surfactants penetrate the surface to safely and easily dissolve tough stains. Can removes gray weathering chalking and oxidation on wood. Fast-acting cleaner works with a simple spray on rinse off application. Cleans up to 1 000 square feet per quart.