I've got a denarius of Severus but it came from an uncleaned hoard of LRB and it is green with a few highlights of silver. (Not something worth posting) I guess the copper in the metal mix soured. Great coins all!
While you have it out, try a new photo - larger, sharper - showing details that you feel make the coin fourree and not just junky. To be fourree, the silver has to be on top of the copper not the opposite. I do collect fourrees but only ones that I find attractive or interesting.