Lichens are a simple slow-growing plant that typically forms a low crust like, leaf like, or branching growth on rocks, walls and trees. Some lichens will eat the stone itself. It is more than safe to say lichens and headstones do not play well together.
The best way to remedy this is to hire a professional who can safely treat the stone. Gravestone Cleaning Services use techniques to prevent new lichens from growing. Scraping lichens off a stone is a very common mistake made when treating the problem, but this process causes lichens to spread faster, further damaging the stone.
Gravestone Cleaning Services will do a major cleaning on the first visit. All visible lichen will be removed and treated; the stone is thoroughly cleaned. After the first visit you will already notice a big change. About a month later, the stone will be treated again. After another month, it will be treated for the final time. The sun, wind and rain will continue to clean the stone for 3-6 month after.