Something similar is indeed the right answer here. You have to take the material above its curie temperature (https://en.m.wikipedia.org/wiki/Curie_temperature

Something similar is indeed the right answer here. You have to take the material above its curie temperature (https://en.m.wikipedia.org/wiki/Curie_temperature https://en.m.wikipedia.org/wiki/Curie_temperature) and then according to physics all preexisting magnetic information is lost.