Hello, I will answer this question in the following aspects:
1. When magnetizing, the voltage is reduced and low voltage is used to magnetize, so that the magnet cannot reach a saturation state, so the magnetic force will be reduced.
2. Carry out high temperature oven heating treatment based on the internal coercive force of the magnet to cause the magnet to demagnetize and weaken the magnetic force.
The answer above is from eight years old. work in Dongguan Jugao Magnet Factory Sharing experience, hope you can adopt it, thank you!