Another problem is you put a frames in your brood box, and you have to dig it back out to freeze it. It gets hard when there is a stack of honey supers on top. So I quit doing it real quick.
Hence the invention of the mite zapper!
I don't use the green frames at this time either. All you have to do is add a foundationless frame in the brood nest and the girls will fill it full of drone comb. I've been experimenting with a 2" deep foundationless layer over my brood nest for drone culling this season. I don't have to do any digging into the nest to remove said 2" frames. I just swap them out or take the hive tool and scrape off the drones on the spot and stick the bare frames (more like top bars) back in and let them repeat the process again.
The drone culling idea has some flaws. One flaw is the bees will still turn some worker cells into drone cells even if you give them green drone comb. Hence you can never really cull all the drones or all the mites.