Here are some things you may see when firing the kiln. The first is not a 4 wheeler accident in the kiln, but what happens when a piece is poured heavy and is not all the way dry. The attachments sometimes do not drain if the slip is thick. The rest was dry but not the thick parts and they blew apart due to the moisture. The pieces do fly and damage other items in the kiln. The second image is what happens when glaze ends up on the kiln shelf. Yes, I was in a hurry and did not maintain the shelf. The piece broke off as the kiln cooled. There were two spots of glaze on the shelf where the cup was sitting. The stress was too much. The shelves have been cleaned and kiln wash applied. You have to chip the glaze off. I use a screw driver and small hammer. The small pin heads of glaze will cause things to stick to the shelve so get them all while you are there. Good to vacuum out the kiln while the shelves are out.