Acid Date Restore

As Elmer Fuss used to say, "Be vewy, vewy caywful. Don't twy this at home."

You sure that didn't come from WWE wrestling?

BadThad I did notice the slight stained area but from your photo it basically blended in with the rest of the coin. Some attempt to do the entire coin but then it becomes an obvious cleaned coin. You may be more successful in applying to only the date itself.
And to your suggestion of being safe with acids, way to late. They even sell weak forms of Sulfuric in auto stores for the Pb type batteries.