Why doesn't my hamster use her wooden chew stick?

Buy her a salt lick or mineral block, it can be attached to the cage or left on the floor and is too heavy for a WW to move very far, it's hard enough to keep her teeth in check and it's flavored so she'll like using it, plus she'll get nutrients she needs. As far as the dough thing goes I'd see if you could chop off bits covered in pee, or clean it off, otherwise it's best to get another. Hamster pee can smell pretty bad after a while and will attract all sorts of bacteria.