There is a special mending slip that can be purchased from most ceramic
shops that do slip casting. It does a great job.
One way we help prevent students from handling greenware is to put dried
greenware on top of the kiln when firing. This also serves the purpose
of making sure the greenware is dry before firing.
If you have room, you may want to put some yellow/black construction
tape on the floor, cabinet to remind students to not pass that line.
Bill in Ohio