"Elementary on up to High School all enjoyed it. The web site helped give real ideas. We kept the clay in an air tight container with a moist towel over the plastic bag and the first piece was as nice as the last used a week later. Comes in 25 lbs. boxes, but the great thing is it is divided into 4 different bags. 18 students used as much clay as they wanted and there was still some left from just one 6 lb. bag."