My male cat does this when he can't get outside and right now there is about 4 ft. of snow on the ground. He is especially attracted to plastic - as in bags,laundry baskets,suitcases,etc. - .His litter boxes (3) are all plastic and I think that is one of the reasons. He eats only cooked meat and fish and dried food. Vet says he is OK. Bad habits die hard. I would also suggest shutting the door. Catnip increases this bad habit (makes him psycho) but the plug in phernomes (sic) make it better. Go figure.