my chin has a large playpen attached to her cage. When in her cage, she uses a litter pan. But when in the playpen, she'll sleep inside a large maze and will pee on the floor. I have since added a 2nd litter pan for her to use when in her maze, but her pee did discolor my carpet. To prevent any more damage to the carpet, I have bought two plastic office mats from Office Depot, and layed a sheet on top of it to prevent her from getting to it. The playpen sits on top of it and is positioned so she can't chew on it at all. Not only does it cool down her play area (it feels cool to the touch) but it keeps any future accidents from touching the carpet. But this works well for me because I don't give my chin free roam of any areas.