Gravestones require proper cleaning from time to time to keep them in good condition. It is advised not to clean them too often because gravestones are porous. Plus, never use household cleansers or detergents because they contain harsh chemicals that can damage the stone. For best results, always clean a tombstone from the bottom and work you way to the top. Cleaning a monument from the top and working down can cause acids and dirt to stream downward and cause staining. If you work from bottom to top, the acids and dirt will be removed right away before they have a chance to spread.
Cleaning gravestones with a power washer is also not recommended because the stone will soak up the moisture and retain it like a sponge, which can cause mold to form. Moreover, do not use cleansers with harsh abrasives and never use a wire or metal brush because they could scratch the stone. To safely remove dirt, fungi, lichen and stains, it is best to use a soft bristled toothbrush or a nylon brush. You can also add a small amount of mild dish soap to the water to remove dirt and stains.