We used regular chalkboard chalk and it wasn't easy to find. The stone was pitted and very difficult to see anything on it. But once the chalk adhered to the printing we were able to see the writing. It was an old German stone "Heir" was the first word we made out. Then the names of the two children buried there. We used the white chalk and it did seem to fill in the worn spots but we went through nearly a whole box of chalk as it wears away quickly and breaks a lot. We did not have any water with us to wash the chalk off. I was assuming rain and wind would remove the chalk in time. Linda