demagnetize
1. [ verb ] erase (a magnetic storage device)
Synonyms: demagnetise
Related terms: erase
2. [ verb ] (physics) make nonmagnetic; take away the magnetic properties (of)
Synonyms: demagnetise degauss
Examples:

"demagnetize the iron shavings" "they degaussed the ship"

Related terms: magnetize change physics demagnetization
Similar spelling:   demagnetise