I have taught high school ceramics for several years. I have found
that it is impossible to recycle all the clay scraps into usuable
clay. Storage is a real problem when you have three full classes of
ceramic students, plus three Art I classes, Art II and Drawing. You
have to have storage for supplies and all classes works-in-progress.
My solution for my ceramcis classes is to recycle in 25 gallon
Rubbermaid cans with lids. Cans are on wheels. Each student
recycles in ziplock bags during the year. Excess goes into the cans.
At the end of the school year, we use left over scraps and soft clay
to plug holes in the ball field, our school lawn and eroded areas on
our campus. I also allow any student who wants their left over clay
to take it home.