What does the term demagnetization mean?

The reduction or elimination of a ferromagnetic body, such as ferrous parts of a sensitive mechanical device, is called demagnetization. Magnetized components made of ferromagnetic materials are usually demagnetized for a variety of reasons prior to the assembly of equipment and devices. For example, it may be needed to remove the effects of residual magnetic fields on measuring devices or buildup of ferromagnetic particles on components. A strong magnetic field may be used to reduce or completely destroy magnetization. Alternatively, if feasible, the material could be heated to a temperature above its maximum Curie temperature, after which it is returned to room temperature in the absence of an external magnetic field.