The blurry pic in the beginning made it difficult. But a point of reference would have given it away. It goes to show that some coins need to be cleaned. Ribbit
I clean most of my copper based finds with a product called "Coin Care". That is how I cleaned this particular coin. I dip a q-tip into the bottle and spread it onto the coin and let it soak into the dirt/corrosion for a while. Then I use the q-tip to wipe off the crud. I think it works great. It is an important tool in my metal detecting kit and I recommend it to anybody interested in cleaning their detecting finds.
I have only found one Buffalo with my machine -1937-D From a homesite from the 20's but I have found a bunch of pulltabs
It leaves a shiny look though. I use a very similar product called Blue Ribbon. My local coin shop sells Coin Care to though.