What can demagnetize a magnet?

Answer 1

• Drop it on the floor a few times.
• Hit it with a hammer a few times.
• Heat it red hot in the stove flame.
• Wrap several turns of wire around it and run a high AC current through for a while.

Answer 2

Factors such as heat, strong vibrations, exposure to other magnets, or physical impact can demagnetize a magnet by disrupting the alignment of its magnetic domains. Additionally, heating a magnet past its Curie temperature, which varies depending on the material, can cause permanent demagnetization.