Abrasive cleaning methods (sandblasting) are not safe for historic masonry. Chemical cleaners are another option for cleaning your historic masonry. Do not use in cold weather (same hazards as water cleaning). Test first: Chemicals can stain, etch, or burn the surface. Always rinse thoroughly and test the surface for a neutral pH.
Use on non-acid sensitive masonry, such as:
- Cast stone
- Most sandstone
- Unglazed terra cotta
Use on acid-sensitive masonry, such as:
- Glazed brick
- Glazed terra cotta
- Polished granite
Paint removal is most successful with alkaline, organic solvent, or other chemical paint removers.