Sometimes after getting it damp and giving it a dusting of baby powder the cracks and grooves will get filled in a bit . May give you a few more features to make it more recognizable.
Be careful ! You do not want to clean a potential valuble coin , I find water and copper don't mix . Old nickels also. Just dust the dirt off with a soft tooth brush dry . Leaving the dirt in the cracks and you will have a better chance to keep the features as recognizable as possible and it will not damage the coin in case it's something special and needs professional attention.
The powder trick works good if you already cleaned it with water and scrubbed it . The dry soft brushing works best after the dirt drys a bit when you get the coin home ,
Try the powder and re post . These guys are great at picking out a few key features and will help you ID that old copper.
, hope this helps , Dew