Question

what are the various ways in which magnets lose their magnetism

Answer 1

1) Via heat: ferromagnet materials will lose their magnetism if heated above a point known as the Curie temperature. At this point, the energy being put into the magnet from the heat will permanently disrupt the magnetic domain structure of the material

Answer 2

Various ways to demagnetise a magnet are

1- Heating
2- Breaking it down into pieces.

for more go to this link
https://www.education.com/science-fair/article/demagnetize/