DS's hamster is adorable but he has very bad toilet habits. He lives in a Habitrail cage which is a bit like a plastic spaceship for hamsters with tunnels and different compartments for different things. He poos in his bed and wees in one of the compartments but won't have any sawdust in there (we are forever putting sawdust and other absorbent stuff in there but he just removes it). As a result there is a constant smelly puddle of wee in one of the compartments and a hamster who eats where he poos. Any idea what we can do as DS's room is starting to smell and it can't be pleasant for hammie either?