Iron Out rust stain remover chemically changes rust and iron into a clear, soluble state that rinses away without scrubbing. Plus it's safe for white clothes and fiberglass, porcelain or acrylic finishes. Cleans toilets, sinks, tubs, dishwashers and exterior surfaces. Cleans and maintains water softeners and whitens, brightens and removes rust stains from white clothing and fabrics. This outdoor formula easily applies with a tank sprayer, cloth or roller and is ideal for removing rust stains from vinyl siding or exterior walls, concrete sidewalks, driveways, fences, outdoor equipment and many other outdoor surfaces.