Iron Out has been the number one brand because it works better on rust stains than any other product. Iron Out chemically changes rust and iron into a clear, soluble state that easily rinses away without scrubbing. It does not contain harsh or abrasive chemicals and is safe on a number of different surfaces including toilet bowls, toilet tanks, white clothing, sinks, tubs, tile, and showers, appliances-washers and dishwashers, water softeners, concrete, and exterior walls. Super Iron Out removes rust and stains from toilets, sinks, tubs, white clothes, water softeners, dishwashers, and much more. Do not use on wood, cars, painted materials, and exposed and corroded rusting metal. Ideal for geographic regions with hard water and high iron, Iron Out is best on rust. 1 lb 12 oz bottle.