When I was a kid there was a man who knew how to do some very creative things with cow horns. The first step in the process was to use pieces of glass to scrape the horns to make them smooth. This pictures shows what he was able to do with the horns that I had scraped smooth.
Mirror Neurons 
I just learned something new this morning. Thanks for directing me here. I totally did not think of horns as possible art material.