Interesting. A litte after that time, aged 13-14, I was interested in coin pusher machines[0], which (despite being gambling) were not age restricted where I lived. Obviously I wanted a way to do better than the system allowed and wanted to know if I could use magnets to pull the coins towards me[1]; some research showed that some "coppers"[2] were magnetic and others weren't, and that it seemed to depend on the date…
I suspect though, that some detail of the various ways he did this just got lost over time. You could probably fish them out with superglue or sticky mastic on the antenna rather than a magnet, for example.
Or maybe the magnet was always used to hold some kind of trap door open rather than directly fishing the coins.