Answer:
Annealing involves heating a metal, and controlling the rate at which it cools, to reduce the hardness of the metal. The exact process will depend on the size and alloy of brass. In reloading brass cartridge cases for firearms, they can become "work hardened" from having been run through the reloading dies several times. We anneal only the necks of those cases by standing them in a pan of water, and heating the case mouth with a torch, then tipping them over into the water.