The disclosure provides devices and methods for magnetizing or demagnetizing a bit inserted in a bit holder without removing the bit from the bit holder. More particularly, the invention includes a bit holder with a cavity containing a magnet. The magnet may be attached to a switch, which allows the magnet to be manually moved within the cavity to an “on” or an “off” position. The bit may be magnetized when the magnet is in the “on” position and demagnetized when the magnet is in the “off” position.