No, unfortunately....
So far I've only tried crystals and the recycled paper pellets (which we're using now). With the pellets we occasionally see a foot print but nothing else so I'm thinking that he's wanting to use the tray but doesn't like the feel of the pellets...he was always quite discreet about where he went outside but lately I've spotted him in the garden beds on soft soil so I want to try sprinkling a layer of soil over the pellets but it's there's been so much rain here it's hard to catch a patch of dry soil.