A guy I know bid on an old non-working hard drive. It was big, something
like ten inches by maybe 18 inches by three inches. I asked him why he
wanted it, and he said he'd show me.

A few days later, the display on my CRT started wobbling. The guy was
holding a magnet a good six feet away from my monitor and rotating it
slightly. Needless to say, he got it out of the hard drive. He had to use
a ball joint separator to get the two magnets apart. Each one was about the
size of two decks of cards, if I recall correctly.

I never found out what the strength of those magnets was. He soon made the
mistake of holding one in each hand. They got too close together and in a
split second they had collided, nipping off a little of the skin from his
fingers in the process. I figure he's really lucky that's all that
happened. I can think of a number of ways it could have been worse.

He brought in the now-stuck-together magnets and surprisingly (to me,
anyway) their magnetic pull for other objects was very weak, like they were
each absorbing the magnetism of the other. I asked if he was going to try
to separate them, and he said no, and showed me that they were both cracked.

I think he was, too, a little.

Anyway, that's all the experience I've had with what were to me monstrously
powerful magnets.