DEFY Wood Cleaner is a powdered concentrate that is mixed with water. It is an environmentally friendly product that safely cleans, brightens, and restores the natural beauty of exterior wood. This product also cleans weathered composite lumber, and removes stains caused by mold, mildew and algae along with the silver gray color that can develop over time. Restores wood and wood composites to their original appearance. DEFY Wood Cleaner is also an excellent choice for cleaning vinyl and aluminum siding as well.