I have an older domineering male cat and a feisty young female half his age. Recently, we had a lot of wind and cold and neither cat wanted to go out. The older cat uses the box a lot, so I set up a separate one for her. He promptly went up and pooped in it. I figured his scent was strong so we carried her out to a protected location when she needed to go. Later, I covered the second box with a towel to discourage him from doing it again. He promptly peed right through the towel. I wouldn't worry except we are going to have to be able for 2 days a one night. We are having a friend come to clean boxes but that won't help if he immediately poops or pees into hers. I don't want to have to separate them. Any ideas? Thanks!!