If I were you I would go to a nursery or a landscape center and ask what they use to remove mold from large stones. I've found they usually have some good ideas and most of the ingredients you probably have at home.

Good Luck

Walking around in old cemete3ries ?

I try to not make a path on top of old graves, but you will sooner or later. Just do your best and do not worry about making a mistake.

-=Allen=-