While there is not a self-cleaning tray-specific litter product, overall clumping cat litter is the recommended product to use with an auto litter device. And this is because the clumps this type of cat litter creates when soiled make it easier for the auto litter tray’s mechanism to detect and then pick up your kit’s toilet waste. Non-clumping litter can also create a wet residue that’s left behind which can clog up the self-cleaning litter tray’s internal workings.