To clean dirt or other particles first try a simple soft bristle brush. If necessary use a solution of mild detergent with water and scrub the surface with a soft bristle brush. Rinse with clean water to remove any cleaning solution that might remain on the surface. If the stone has a white stain deposit (efflorescence) please contact our office for recommendations. Never use wire brushes, acid cleaners, power washers, bleach, paint remover or any other type of concrete cleaner.