New to this so take my comments with a grain of salt.
I'm going to say F15 to F20 based on this example. For example, your coin's 'Liberty' is better defined than this example but not as good as F20's I've seen.

But I'm also going to say 'cleaned', but I'm not sure. But I'll tell you why I'm saying this. The green circled area has a nice gradient between the worn area and the dirty area. This looks very natural to me.
The yellow circled are doesn't have the same gradient. It looks like someone came in there with a brush or some other sort of tool to clean that area.
Why just this area would be cleaned and not other areas doesn't make any sense. So I'm probably off base here with the 'cleaned' declaration.
I'm also realizing that the worn area within both areas that I've circled look to have the same brightness (dullness?). I would think the cleaned area would be brighter, but its not.
So, now I'm really doubting if its been cleaned.
I just wish my boss at work was as definitive as I've been here.
