I have the exact same problem, and what I did was purchased a little add-on that makes the edge of the litter box higher, forcing my kitty to lift his feet out of the box instead of dragging. When he does it, I watch him and he shakes his paws. It doesn't keep every spec inside the box, but it works best out of any other litter box I have used. There's really no way to keep it from coming out of the box. If you don't like the sandy type litter, try the new crystals. They are larger, so they don't track outside the box as much.