A few months ago one watch I own was overhauled. I really only wore the watch a few times. One day I was wearing the watch the watch kept very erractic time.
I took the watch back to the watchmaker. He had the watch a couple weeks. I asked him what the issue was with the watch. He told me the watch was magnetized. I thought to myself how can this be the watch sat in a drawer and was only worn a few times.
One day I had the watch sitting on top of my desk. The watch was in a jewelers envelope waiting on a new strap installation. In the drawer was a high powered magnet sitting under a few letter envelopes.
Today I asked me wife did you happen to see the big magnet that looks like a doughnut? She replied I put it in an envelope in the middle drawer of your desk. Well that watch sat on top of the magnet with a few letter envelopes inbetween the magnet and the watch.
So no need to wonder how the watch was magnetized. This is an old magnet that was used to reset the old type tire pressure monitons on car wheels. The magnet comes in handy for finding small metal parts that fall on the floor but I am tempted to just throw thw maget out. However I put that magnet in my garage stuck on the side of my tool box where it should have been stored.

 

I had an old magnet from a missile radar, it was extremely powerful and I used it in the garage for general magnet requirements.

One day my young son found it and went testing everything for magnetic properties. I was a great learning experience for him,

trees; no
bricks; no
side gate; yes
motor bike engine; no
refrigerator door; yes
28" CRT TV screen; no
etc. etc. etc.

That evening we sat down after dinner to watch TV, only to be greeted by a purple screen and a son vanishing rapidly to his room.

One of the radar techs at work fixed it for the standard fee (carton of beer) and I showed my son about magnets and things they must stay away from.

Nothing simpler than two blokes with a powerful magnet in the garage. It was a bit of a bonding experience.

I don't think he'll make the same mistake now though .

 

I did the same thing to our 19" TV when I was 10 or 11. Oops. Fortunately we rented our TVs so my father called up and got it exchanged.