Hi RF1,
Your guess is as good as mine regarding that grooved artifact. I wouldn't immediately consider it "junk" Is it Copper? Might be a beat-up coin. Unknown purpose.
Found a 'grooved-up' copper disc at a late-1700's/early-1800-'s site. There are still some faint markings that suggest it was a coin. It has three square holes on its perimeter -- possibly punched with a square nail. It is about the diameter of a modern quarter... A mystery.
Cheers,
--Bert