To demagnetize a magnet, cause disorder to the unit magnets within the magnetic material. Strike the magnet first with a hammer, heat it strongly, and then subject it to AC current to eliminate magnetic ability completely.
- Strike the magnet
Start with putting the magnet through physical abuse. Use a hammer and hit the magnet repeatedly. This causes disorder in the unit magnets inside, diminishing magnetic ability.
- Heat the magnet
Use a pair of tongs to subject the magnet to a flame. Be careful as magnets tend to become hot after a few moments of exposure. To avoid getting burns, wear gloves and use a long pair of tongs to keep your hands as far away as possible when the flame is on. Heat the magnet for a minute or two, and allow it to cool down.
- Expose the magnet to alternating current
Once the magnet cools down, the magnetic ability must be greatly reduced. To demagnetize completely, connect the magnet to an alternating current generator and leave it connected for a couple of minutes. The alternating current causes the dipoles of the magnet to change direction again and again. Soon the dipoles stop reversing, and the magnet is completely demagnetized.