Cleaning for cast surfaces including pre-cast concrete, non-polished natural surfaces including flamed and honed granite, tumbled and honed marble, cleft and hone slate, quarry tile, flamed and honed limestone, unglazed ceramic tile, porcelain tile, cement grout, brick, concrete, mortar and masonry. Miracle Sealants Phosphoric Acid Cleaner is designed for use on interior and exterior natural stone, pre-cast concrete pavers, concrete and masonry. Fast-acting cleaner formula helps remove grout and mortar residue, hard water deposits, rust and more.