I don't think liners would have much to do with it because I don't use them and the best scoopables still stick and clump to the bottom over time. the older the litter is, the more it sticks. Even when you add fresh, there's still some of the used mixed in there. I recently learned from QueenScoopalot to use a puddy knife when a few cats prefer to pee on one corner of the pan, if ya don't want carpel tunnel! I TRY to remember to spray the cooking spray (Pam stuff) before filling with fresh after washing!