Bugs. Bugs everywhere. Help

[Poekie]

I have 2 hamsters. One of the cages has been filled with tiny grain beetles for a while now (I was working on getting a new cage). The other cage has just started gathering beetles too. The plan for now is to finish the new cage and then empty out both cages fully and remove anything that could have beetles in it. Then I'll have to refill both cages and just hope that they won't show up again. I'm terrified of them not leaving. They're not doing any harm to the hamsters themselves, but they do likely eat some of their food. What do I do if this doesn't get rid of the bugs?