I explained to them that I could fire their creations, with some limitations. Man that was hard trying to to explain to those five and six year-olds.
I discussed a few basic principles, and let them go.
It was funny because one little boy worked for a while on this "snow monster" and earnestly said, "I'm done. Now, will you go burn this?" So I told him that it had to dry out before I fired it in the kiln . . .