Can you solve the MAGNET RIDDLE? ft YouTube CEO Susan Wojcicki

The magnetized metal piece will have a north and a south pole. If you swipe the non magnetized metal over it, it will get attracted to one pole, dragging the (non magnetized) metal to that pole. In this case you are holding the magnetized metal in your hand and are swiping the non magnetized metal.

Now the other way around.
If you swipe the magnetized metal (using the north or south end) over the non magnetized metal. It wouldn’t drag it to a pole, it would only drag it to the non magnetized metal. So you know you are swiping the magnetized one and the non magnetized is firmly in your hand.

Now rinse and repeat until you are sure of it. Should even work in complete darkness.

Of course this gets nearly impossible if the poles are arranged in a way that the distance between them is small.