Tombstones in damp, overgrown cemeteries are likely to harbour moss and lichens. Moss is green and cushiony, while lichens are greyish-green and scurfy. Unlike lichens, however, moss grows rapidly and spreads across tombstones, eventually covering them completely. Although neither lichens nor moss damage tombstones, these growths may conceal name engravings in tombstone surfaces. Moss and lichens also detract from tombstones' aesthetic appeal. Carefully clean moss and lichens off tombstones using appropriate materials.
Attempt to remove the moss and lichens with plain water before using harsher solutions. Begin by drenching the tombstone with water to soften the moss and lichens.
Scrub the tombstone gently with a soft-bristled brush. Remove as much moss and lichen growth from the tombstone as possible.
Treat any remaining moss and lichen growth with an ammonia solution. Begin by filling a pail with 1 gallon of water. Mix 1/2 cup of household ammonia into the water.
Dip the brush in the diluted ammonia. Gently scrub the diluted ammonia onto the tombstone to remove the remaining biological growth. Carefully scrape moss and lichens off the tombstone's engravings using a wooden Popsicle stick.
Rinse the tombstone thoroughly with fresh water.
Never use acid-based cleaning solutions, bleach, heavy-duty cleaners, household detergents, soaps or all-purpose cleaners on tombstones; damage may occur. Never use abrasive materials, including metal scrapers, wire brushes and coarse pads, on tombstones; permanent scratches may result. Spot-test the diluted ammonia on the tombstone to inhibit any discolouration.