Akona® Akonastone™ Multi-Purpose Cleaner is a phosphoric acid-based cleaner that can be mixed with water to form a mild cleaning and etching solution for use on concrete, masonry or used as supplied to remove efflorescence from mineral based surfaces. Use for cleaning and preparing concrete and masonry surfaces prior to repair patching or the application of a coating or sealer. Helps to remove rust from iron surfaces and tarnish from copper. Helps to remove hot tire marks on concrete. Helps to remove oil based stains, dirt, and grime from mineral based surfaces.