any way to stop ferrets pooping in hard to clean places?

My original ferret had a couple of usual places he would poop when out of the cage, which was super convenient and managable with corner boxes and newspaper. When I adopted a friend for him this quickly changed. The new ferret poops everywhere, and her influence has rubbed off on the other. They will constantly poop and pee under my bed, which is a difficult task to pull out and clean, amongst other places. Is there any way to dissuade them from pooping in hard to reach spots? Its been going on for almost two years now.