Restores a new appearance to slightly dirty or discolored limestone poured concrete, precast, poured aggregate and tavertine.X-190 Limestone & Concrete Cleaner is used in restoring a new appearance to dirty or discolored limestone, poured concrete and walkways, pre-cast or poured aggregate, travertine and more. X-190 Limestone & Concrete Cleaner may be used as a bleach to whiten concrete or limestone. X-190 Limestone & Concrete Cleaner cleans without leaving yellow stains. X-190 Limestone & Concrete Cleaner is safe on glass and contains no hydrofluoric acid.