I planted some flat stones earlier today, myself. Okay, they weren't really stones. They were ruined kiln shelves. One of my kilns didn't turn off automatically like it should have and went to some ridiculously high temperature, probably north of 2500°F. Everything in the firing just sorta collapsed into a mishmash of blistered pots and warped and broken kiln furniture. First time I've ever used a hammer and crowbar to unload a kiln. The shelves found a new use as pothole repair agents.