To clean granite tombstones, first examine the stone for any cracks, flaking or other weak areas. Do not put more stress on damaged areas to prevent further damages. Use a small pump sprayer to wet the stone thoroughly. This softens any materials on the stone and makes the cleaning easier.
Start scrubbing with just water and a soft bristle brush or plastic scraper. Avoid using detergents that contain compounds such as sodium chloride, sodium bicarbonate or ammonium carbonate as they lead to formation of soluble salts below the surface of the stone. Wash the stone from the bottom to the top to reduce risks of staining and streaking. Use non-ionic cleaners since they do not produce harmful salts or leave additional stains.
Do not use metallic scrubbers when removing any organic materials or bird droppings. For efficient cleaning, consider using plastic scrapers, which are soft and flexible and can get the job done without damaging the marker. Apply the cleaning solution on any stubborn material before scrubbing it. When cleaning carvings and lettering, use a soft bristled toothbrush.
After cleaning the entire tombstone, wipe it with paper towels or soft cloths to prevent the stone from streaking as it dries.