I have the large flat stones, profiles, and one each of the sharpmaker triangles I have always used them dry without any problems. When the stones start to get shiny from the metal being removed I wash them with some bar keepers friend and they look like new. I have had my flat stones the longest (about 6 yrs.) and they still look almost like the day I got them, there are some steels like titanum that will leave permanent marks on the stones but they are very faint. You also wont need to worry about flattening them.