Miracle Heavy-Duty Cleaner is a revolutionary patent-pending water-based industrial cleaner designed to remove grout haze, built-up grease, dirt and stains from all ceramic, porcelain, grout, glass and Natural Stone. Miracle Heavy-Duty Cleaner will not hurt or remove the finish or polish on acid sensitive surfaces including marble. Now for the first time an industrial strength cleaner as strong as an acid without the harmful effects. Miracle Heavy-Duty Cleaner addresses dirt and grime at the molecular layer penetrating deep underneath the staining agent. It is a non-corrosive water based cleaner with a mild pH. It leaves behind a monomolecular layer bonded to the surface that makes the surface more resistant to future dirt and stain build-up. Unlike acid cleaners, it will not harm your skin even though one should always wear protective gloves and eye protection as an extra safety precaution whenever cleaning any surface.