1985 Dime... I say a combination of 32 years of circulation wear on a Reverse that started with a bit what is called a Struck through grease strike. Not a major Mint Error.
I vote minor error, struck through grease, then well-circulated, as @paddyman98 indicated. Not gonna be worth much of a premium (maybe just a teeny-tiny bit, to the right interested person), but it's a cool find.
