Concrobium Mold Stain Eraser is a powerful cleaning solution that targets tough and embedded mold and mildew stains on outdoor and indoor surfaces. Perfect for black mold stains. Ideal for: Tile showers, bathrooms, basements and outdoor furniture, decks, patios, fences, walkways, railings, siding, gutter and roofs. Works on: Wood, composite wood, concrete, masonry, drywall, grout, stone, fiberglass, tile, plastic, laminate, aluminum and metal. Green technology - contains no chlorine bleach or VOCs.