I might even give this a try. My cats sometimes try to sit on the edge of their litter box while they are "going" and their weight causes the boxes to tip, scaring them and creating a mess for me. I don't think Trevor could even tip a Rubbermaid container filled with litter! Now if I could only get Andy to stop covering with such gusto! He digs so furiously that sometimes he creates a little pile outside of the box.