This is what I have come up with since our fridge isn't magnetic.
The kids LOVE IT! (yes, my kids are naked AGAIN).
I got an alphabet poster for a teaching store and used rubber cement to paste it to the metal. The oil pan had a grease coating on it which came off with SimpleGreen. I didn't want to put (or try to put a hole in it for hanging) a hole in it so I use the 3M picture hanging velcro. It worked famously and at only 22 months old! When the master the alphabet, I hope to make a new board with phonic sounds.