NO NO NO NO NO! Shaving cream is bad for stones and it has little or nothing to do with the PH. It is the lanolin that is waxy and the other ingredients! Your face and beard are not granite or limestone, What makes you think shaving cream is appropriate? It might be it is white...well, so is Mayonnaise, white paint, clown makeup... come on! I have heard of people using flour (which feeds lichen and makes GLUE) and baby powder... just leave the stones alone! It is not YOURS. It was paid for by your ancestor but you are not the only descendant and we others would like to be able to go see the stone intact! Think, please, use common sense. An old stone can react to almost anything you do to it, expept photograph it! I am serious about this, NOT wanting to pick a fight,.. but when I find a stone 200 or 300 years old, in decent shape it is usually one not many people knew where it was and haven't messed with!! You are most right about mowing over them and up against them... BAD! It is hard to get cemetery keepers to use weedwhackers and the least thick string that will do the job on the grass and not gouge the stone. Seriously, you who are asking about stones, subscribe to Tombstones. it is a rootsweb list. Cacky