Tin Containers as Fridge Storage

I've seen this idea floated on Pinterest for a while now.  Allegedly, you could put a magnet inside a tin container and it would magnetize the whole thing to stick to your fridge.  Not true.  BOO.  Still, with a bulldog clip, you can still take advantage of your cute old tin (in this case, an old bank) for holding pens.  I have a Chiclets tin holding coupons as well, but in that case I don't have an open side to use the clips on.  I need to stick magnets to the back of that puppy for it to be functional.