Hi; First soak it in Lemon Juice for a few hour. Take it out and use a tootpick to PUSH, not scratch, the dirt away GENTLY ok. Second, We need a side View picture of the Shank. That will give us the Date range. IF you can make out ANY lettering off the back PLEASE write it down here even if the words are not complete ok. Just leave a BLANK space for any letters you can't see. Then We can nail it for you. I can tell you it is a 2 iece Button which maakes it 1820 - Present. I thinknyours will come in about 1850 or so ok. Good Luck. We await. PEACE:RONB