yep- buy a can of PAM cooking spray and every time you change the litter- spray the tray with the pam (the inside bottom only not the sides or the cats will start licking the pan
Let it sit to air dry for about 5 minutes and then dump the fresh litter on top
There is something similar at PetsMart-- It smells kind of like baby powder but it keeps litter and all the crap sticking. It also keeps the litterobox from smelling stinky.
the only problem with linersis that most cats will rip them appart when they are trying to cover the litter. They claw to get the litter to cover their business, and thier claws rip the flimsy plastic.
I had no choice when Vagabond had her kittens, I had to take the liners out, because she would claw and claw and claw when she would go to the bathroom. i didn't want any of the new kitties to get peices of plastic in them... bad for the digestive track lol