Hi; It is a Draped Bust Large Cent circa 1820's. Please post a picture of BOTH sides AFTER cleaning and we can nail it for you ok. Nice Find. PEACE:RONB
Soak it in room temperature hydrogen peroxide for several hours. Handle it very gently and don't rub it much; the peroxide should lift a lot of the dirt and expose more of the detail.
Most ground recovered coppers don't value well due to environmental damage. You won't devalue the coin by Glenn's method of cold peroxide. I use it myself. I recently recovered an exceptional large cent, take a look at this...