Traditional Cleaning Methods:
Traditional Cleaning methods can usually be broken down into 3 categories: Water, Chemical, and Mechanical
Water: A low pressure water wash is often considered “not enough”, and a high-pressure wash or steam cleaning can destroy the concrete while forcing moisture deep into the concrete itself. Since concrete is porous it may absorb moisture, leading to spalling or cracking. This excess water will also contribute to bringing soluble salts from within the masonry to the surface leading to the formation of efflorescence
Chemical: concrete may dissolve easily with certain chemical, cleaners, and especially with de-icers even in a diluted form. Some chemicals can change the color of the masonry itself as well as leave a hazy residue despite a heavy rinse. They can react with components of concrete to create soluble salts and eventually lead to efflorescence.
Mechanical Cleaning: hand tools, grinders, sanding discs, wire brushes, etc. all abrade the contaminants off the surface with damaging results.