If access can be opened up at bottom, I would go with what IntelligentFish said. Maybe take a piece of conduit and tape a long knife to the end? If you have to go through a damper, could be a real pain. See if you can talk them into Spring trapout. I always stress less bees, less honey, calmer bees, etc. Good thing this chimney isn't attached to a working, but infrequently used fireplace - can you imagine the chimney fire?! :shock:
JC