That works ... sort of. How much magnetism (if any) you get, and of which
polarity is a function of where in the waveform the coil is when you switch
the current off.

Jim



Yes, a large coil with AC can be used to degauss by
withdrawing the coil to several feet. Putting a tool or
tube in the AC field and switching OFF will magnetize
because the induced field is cut suddenly.