Just to add to Sue's report ...
While at home, I guesstimated and cut open a plastic container to use as a corner litter pan for Baby since he likes to dump in the bottom left corner of the cage. Well, I guessed the size wrong, so it's a little small, but I put newspaper on the bottom and "showed" it to Baby, who did do a trial back-up into into ... while I held my breath and hoped he'd do his business too -- LOL -- but he didn't. Later cutie checked it out and tried to move the newspaper and container. I forgot to insert a whole into the container, to clip to the cage.
I left a few folded pieces of newspaper on top of the cage. I'll get around to making a hole in the container and drop more newspaper off at the shelter. Since Baby normally backs up into that corner, I'm hoping the container will work. If yes, then I'll make a better sized container.
Failing that, Sue suggested using incontinence pads, attached to the sides and bottom of the cage.
Hopefully we'll be able to solve the messy cage problem. That will just leave the messes that Baby makes while free roaming.
...Nancy