I found this in the centre of a cellar hole under a stone. I believe that the foundation wall fell into the hole a long time ago as there's good layer of soil built up.
Once I got the rock out this was another 6" down.
65mm weight 1.017kg/2lb 3 7/8oz.
Tokens are 1812/3
Wire brush. Sometimes I use "Iron Out", but lately I just start pounding on them with a 4 ounce tack hammer to get the big stuff off, then wire brush. Yours doesn't look like it needs the hammer treatment.