Chemical or physical treatments, such as sandblasting, that cause damage to historic materials shall not be used. The surface cleaning of structures, if appropriate, shall be undertaken using the gentlest means possible.
How To Clean Historic Materials Using the “Gentlest Means Possible”
Part 1: Cleaning Historic Masonry
Part 2: Cleaning Historic Metal
Part 3: Cleaning Historic Wood
Part 4: Cleaning Historic Stucco
Part 5: Cleaning Historic Ceramic Tile and Terra Cotta
Part 6: Cleaning and Hazardous Material
