Hi Treacle
Putting twigs or branches in Treacles cage might stop bar chewing, and is very enriching
twigs and branches all sorts of trees like birch, oak, hazel and beech trees are ok. No harmful substances, and this is what hamsters would probably use to wear down their teeth in the wild
dried bread and dog biscuits are a good idea aswell (you probably already know about that :P )
Im on msn right now
Leafpool
AND dont forget to clean the twigs and branches like you said