here. I had never checked any of my black cabinet “coins” for magnetism before reading this, but when I did, it somewhat opened my eyes. The crude ones with wide borders, incorrect calligraphy or design, etc., were not all magnetic, but the ones that looked pretty good from a distance and had to be carefully examined for casting bubbles and overall size were all magnetic. (One of those business card-type refrigerator magnets slapped on the side of your computer case makes for a handy way to check coins for magnetic properties.) Most of the time It won't be a really useful diagnostic, because the coins it reveals as fake are so underweight and/or undersize that you already know their nature before you try the magnet on them. However, if you don't have an accurate small scale, one of those magnets might help at a dealer's shop or a show. It would also be handy backup confirmation to convince that tiny minority of folks who insist that 25% underweight is “within tolerance”.