Is this for real?

Is "demagnetize" the word this/these company(ies) really uses? And they're good for speakers? I could be wrong, but isn't it the electric signal from the amplifier what turns your speaker's voice coil into a constantly-varying-in-charge electromagnet that then, based on the way magnets attract and repel on like and opposing charges, moves back and forth within the fixed constant charged field of the loudspeakers permanent magent (Neodymium, Ferritin, etc.) that in turn moves the whole speaker cone--since the voice coil is attached to the speaker cone. Wrap a bunch of wire around a nail, hook each lead up to a battery, and it'll pick up metal shavings and whatever else that is metal. That's how I'm kind of reasoning it--same things? (The voice coil is wrapped around the voice coil former isn't it?) I don't see how it could work for speakers. If it does what it claims it seems it could demagnetize your speaker's magnets (and ruin your speakers!). Two ways to get rid of a magnets charge is to bang'em or heat'em up. So you could slap the top of all your components once a day and stomp on your speaker cables to fix the problem (I don't recommend it). I'm skeptical: I have a hard time believing they do what they claim.