This how-to video is about how to remove a hickey with a battery. This is useful if you want to hide it from your boss, your mom, or even your girlfriend (shame on you, really).
You will need a standard AA or C size battery. You rub the hickey with the negative, flat side of the battery. You will need to do this firmly for a few minutes. Although it does not completely remove the hickey, this process does reduce the appearance of the mark.