First, if possible, remove them early in the year, while the colony is still small and easy to manage. My last job, done in late April, took less than three hours. Last summer, when colony populations were at their peak, most jobs took all day. More bees, brood comb, and more honey also mean more stings and more containers to fill.
The non-beekeeper assumes that with all the pounding, ripping of plaster and lath, and sawing, that the bees become riled and will come boiling out of the opening, stinging everything in sight. In fact, they become confused and relatively quiet. This is good, because you shouldn’t use a smoker inside someone’s house, first because it’s a fire hazard, and second because the smell will linger long after you are gone. I keep a spray bottle of sugar water, scented with anise or vanilla, spraying them about as often as I might use the smoker.
Always assume the homeowner has sprayed insecticide into the colony. Unless you can know that they didn’t, most of the comb, at least near the opening should be discarded. In the first photo, lower left, the yellowish area is spray foam insulation. It is surrounded by empty combs with three full combs to the right. Sometime last year, the homeowner attempted to eliminate the colony by cutting a hole in the wall, spraying insecticide and then sealing the hole. He missed most of the colony, but made that area uninhabitable.
In the second photo, upper right there is a black spot, about the size of a softball. Photo 3 shows a close-up with the adjacent comb removed. This is what’s left of an old winter cluster. Apparently the old colony died out one or two years ago and was replaced with a new swarm. Less noticeable in the photos was that this colony had a long history in this house. The bees in April occupied only the top 20 inches or so of the cavity, but the comb extended from the ceiling to below the floor level and spread into the areas on the opposite sides of the studs.
If you are interested in taking bees out of walls, I recommend the book Honey Bee Removal by Cindy Bee and Bill Owens. It’s available from Root Publishing for $19.99 by calling 800-289-7668.