Removing mortar from back of encaustic tiles?
I have four Victorian encaustic tiles that have a lot of mortar stuck to the back of them. The mortar protrudes 3/4" in some places, and since I plan on reinstalling the tiles I can't leave the mortar attached if I'm to have a flat surface. The mortar looks a lot like cement. What would be the best way to remove it without breaking the tiles in the process?