I received a few coins today, this Urbs Romana follis being one of them. I took a chance and ventured at my first cleaning--well, removing some of the sand patina from the design. From the onset, I went very slow at carefully working around a few areas on each side--can you tell? Hint: it's subtle around the emperor's face and the wolf.
If someone has infinite patience, this would be a good hobby for them. I'm not a terribly patient man, but I'm pleased how I clarified a few areas without causing damage.
After (shot with artifiical light):
Method: soak in distilled water, then very carefully scraped a few sandy areas with an Xacto #11 blade--under a loupe. Dried coin, and lightly burnished a few highlight areas with a soft rose thorn to smooth the work.
Here's the seller's attribution--I need to do some more research:
Urbs Roma follis from Rome mint. RBE in exergue, 2,46 grs.