Yes the moths seemed to like my cork tunnel too! Don't want to alarm you but they can end up in food cupboards as well so it's important to kill any moths you see and clean the cage and toys. With wood bark items or the cork tunnel I wouldn't risk it due to the little crevices, but sounds like you have it sorted. You can even freeze fitch in smaller bags if you're worried about. I think it's from the food though. The moth eggs are just in it and under certain conditions they can hatch out - eg when it's nice and warm with the central heating on and a warm hamster sitting on top of the food! Your jar sounds fine but I'm belt and braces now and use a completely airtight lock and lock box
. I ended up with them all over the house - in the kitchen cupboards - ugh!