Leaving flowers or a flag at a headstone are wonderful ways to show love for your late loved ones. Another good way to demonstrate love and respect is to clean the headstone. Over time, even the smoothest gravestone will accumulate soil and mosses that will begin to break down the stone. This may cause cracking or undue wear on the marker. Cleaning the headstone will help preserve it and protect it from the elements. However, you must be very careful when cleaning a headstone, especially if it is old. Certain chemicals could seep into the stone and cause more damage than the dirt and moss. It is also important to use the proper tools; metal scrapers and wire brushes will only scratch and crack the headstone's surface.
Gently tap the headstone and look it over for hollow places and cracks. If the marker echoes or has large cracks, do not try to clean it. Cleaning a hollow or cracked stone could leave fluids inside the stone that will only destroy it from within. If it is solid and crack-free, clean it gently.
Saturate the stone with warm water. This fills the pores of the stone and prevents it from soaking up cleanser. Before applying cleanser, remove as much dirt as you can with a soft-bristled scrub brush. Move in firm-but-gentle circles from the bottom of the stone up.
Scrape moss and lichens away with a wooden scraper. Soak a sponge with water and squeeze it over the lichens, then press the scraper firmly against the stone and draw it down. This should scrape away most of the lichen. If not, use a soft-bristled brush to scrub pitted and rough surfaces.
Clean remaining lichen away with nonionic soap. These soaps are electrically neutral and don't leave soluble salts behind when they dry. Photo-Flo is a nonionic soap made by Kodak. Dissolve about 1 cup of soap in 1 gallon of warm water and soak a sponge in the solution. Squeeze the solution over the lichen, soaking it.
Scrub the lichen with a soft-bristled brush. The soap should wash away any remaining lichens and dirt. Gently rinse the headstone with clean water every few minutes to avoid streaking or leaving detergent stains.