1) Degauss 2) Demagnetise 3) Erase 1) Delete 2) Demagnetise 3) Erase 4) Make nonmagnetic 5) To remove magnetization from 
The removal of any magnetic fields or particles from recording and playback heads on a camera or audio tracker. (See `degauss`.)
to reduce the magnetic flux density of a magnetized substance along a demagnetization curve NOTE - The term to demagnetize applies mainly in permanent magnet technology.
De·mag'net·ize transitive verb 1. To deprive of magnetic properties. See Magnetize . « If the bar be rapidly magnetized and demagnetized .» Am. Cyc. 2. To free from mesmeric influence; to demesmerize. -- De*mag`net*i*za'tion , 
[v] - erase (a magnetic storage device) 2. [v] - make nonmagnetic
demagnetise verb make nonmagnetic; take away the magnetic properties (of); `demagnetize the iron shavings`; `they degaussed the ship`
to remove magnetization from.