Self-cleaning litter boxes employ technology that automates the litter box emptying procedure. Some models have electric combing mechanisms that automatically scoop the clumps out of the litter box into a sealed, disposable-bag-lined container after the animal has used it. These models use a pressure pad or an infrared light to determine when the cat has left the box and will comb the box after a pre-determined amount of time has passed to avoid disturbing the cat. Other designs take this one step further by connecting directly to a home’s plumbing (faucet connection and drain) so they can wash, rinse and dry the permanent litter pellets automatically. Simpler designs exist as well; for example, some require the owner to manually shake the clumps into an easy-to-remove tray. Another variant has an enclosed sphere which rotates as it sifts out the clumps and deposits them in a drawer below the sphere. A new method involves incorporating sifting functionality within a sifting litter liner. Some automated litter boxes incorporate the use of a two-belt system. The top belt has litter ready to use while the lower belt has a batch of litter ready “on hold” for when the cleaning process takes place. As the litter on the bottom belt is moved up to the top, is it evenly distributed across the width of the top belt.