Custom Building Products TLSAC1 Sulfamic Acid Cleaner, 1-Pound Lb, sulfamic acid cleaner, concentrated crystals that will remove dried cement grout & mortar residue, ideal for neutralizing efflorescence & etching concrete Adds Extra shine to your product Manufactured in China Removes dried Portland cement, grout haze and mortar residue from tile, concrete and masonry Safe for use on colored grouts Removes hard water deposits, efflorescence and also etches concrete Use on all colors of grout, tile, clay pavers, concrete and masonry Do not use on marble or other polished stone May etch some glazed tile