Found at a lot that was a school from 1910 till the late 1950s - small badge, aluminum? Has star in center with red and white accents, and small lightning bolts around the star. Must be some kind of cereal/radio/etc. premium but would love to know what it was for. I soaked it almost 24 hours and it didn't clean up much unfortunately. Looks like a pin was attached to the back as you would expect.