What ive done to prevent my boys from shredding their liners is i putt he main liner down on the pan and clip it in place really well. Then i take another piece of fleece and clip it down loosely. My guys seemed to be interested in shredding the liner so they could sleep under it, so this method has basically eliminated it! They chew on the top fleece sheet but that doesnt matter. They do chew the main liner a bit, but not enough for it to be unusable for a long time.