Cleaning black stains from gravestones?

Question: Cleaning black stains from gravestones!?

This isn't lichen but like ground in soot!. and the water with plastic brush doesn't even touch it!. what can I safely use to clean this!?

This question should maybe be in the cleaning section but I imagine more of us involved in genealogy have dealt with this!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

It depends on the stone!. Marble's a little more finicky than granite or limestone!. But you can use a little kitchen cleanser with a scrub brush and water on any stone!. If it's marble, don't use any chemical cleaners because they can discolor the stone!. For granite or limestone, you could spray it with a normal stain pre-treater like Oxyclean or Shout!. Let it sit for a couple of minutes, then scrub with warm water!.Www@QuestionHome@Com