I recently purchased Peter Fritzsche's 2008 "Hamsters" book, and, while reading the section on toys/furniture for said rodents, he said that, in addition to wood and clay, you could make your own out of papier mache, which I thought was rather interesting (he's got a PhD and has been studying hamsters for 30 years, so I assume he knows what he's talking about).  He said wood glue was okay for the wooden stuff, so, as that's very similar to PVA, I'm guessing white glue would be okay for the papier mache, although I imagine the old dependable flour mixture would probably be safer still.  And, of course, don't use paper/newsprint with ink/printing on it, or any other kind of potentially harmful chemical treatment.

I haven't owned a hamster since I was a child, but, had I known it was permissible, I almost certainly would have tried making them some papier mache playthings.  I just thought I'd throw this out there for those of you, or your children/grandchildren, that may have a hamster and might want to give it a try.