Once the bees have set up housekeeping for more than a few days, the job often becomes more difficult. Sometimes, much comb (beeswax), brood and honey are stored in the wall of a structure.
Simply injecting a pesticide in the wall to kill the bees is risky.
The comb will attract wax moths and mice. The honey will attract ants and other insects and may ooze through the wall or ceiling when comb melts during hot weather.