I never heard of this before, and it's awesome. Apparently, in the heyday of the hobo (circa 1930), a popular way for them to raise cash was to carve totally new images into one side of a nickel and sell it folks at train stops, etc. There's even a collector's society and quite a bit of eBay business (tip: the "Bart Simpson" ones are probably fake).
It sure beats the hell out of "how about a quarter, buddy," or my perrenial favorite, "I'm out of gas."