Reason: Because there are magnets in the mobile phone, it can't be placed near magnetic storage media, such as computer disks, credit cards, telephone magnetic cards and other objects.

Supplement: degaussing is a common technology to destroy the stored magnetic tape data. Using degaussing equipment like a box to change the magnetic field of the tape can effectively destroy the data on the tape. In this way, the tape (without pre-written tracks) can be reused. Degaussing can also be used to erase the contents of hard disk, USB thumb drive, smart phone or floppy disk. Of course, the magnetic field also degausses the mobile phone.