It's de-magnetizing that is tricky, so i am told. It can take quite a few smaller zaps in reverse polarity to get to neutral in the gap.

If one doesn't remember to switch the polarity of the gausser back, your magnet will be charged backwards, effectively reversing the phase of the driver's terminals.

FWIW, near a working gausser/magnetizer is not a healthy place for humans to spend any length of time.