Sure Klean® Heavy Duty Restoration Cleaner is a concentrated acidic cleaning compound for the removal of heavy atmospheric staining from unpolished masonry. Used properly, Heavy Duty Restoration Cleaner dissolves heavy carbon and many other stains commonly found on masonry buildings in highly polluted areas. Dilute with water to produce a cost-effective, general-purpose restoration cleaner for brick, granite, sandstone, slate, terra cotta and many other masonry surfaces. Cost-effective concentrate reduces shipping, storage and container disposal costs. Proven effective for cleaning the dirtiest buildings. Safer than sandblasting. Will not damage masonry when properly used.