Cassette demagnetizer

[1][2] The passage of magnetically charged tape over the metallic parts of the tape deck imparts a magnetic polarity that can reduce fidelity in recording and playback.

The wand's advantage lies in its demagnetizing other metal parts of the tape path, not just the heads.

Used carelessly, it can increase the magnetization of the heads; if used too close to tapes, it can erase them.

[citation needed] A third design consists of a cassette shell with a head cleaning tape wound on the spools and a magnetic disc mounted above the head cleaner tape.

These work by feeding the record head a high-frequency signal, whose amplitude is great at first and then is reduced to zero over a few seconds.