The first time cleaning old kiln wash from my shelves, and I don't have grinding equipment so I thought it would work to have them soda blasted. But the surface is now rough and there are lots of places on all shelves where spots of stuck kiln wash remain. Mistake! It was just too easy and inexpensive.
I want to flip the shelves and use the smooth side. Do I need to make the rough underside smooth for some reason? Will those bits of old kiln wash flake off in a firing? They are stuck on too hard to remove by hand with a knife.