Could this be a improperly mixed alloy stripe or a strike through? Or it been struck on a damaged planchet. The cent is toned but isn't toned on the stripe.
This is just a guess, but maybe the coin was in an album that has slots to hold the coins. They were very popular in the 50's & 60's. Chris
Simply circulation discoloration We don't know exactly what liquid or other substance touched the coin, after it was in circulation. I see a 'line' from about 11:30 to 4:00 that looks like it might have been a improper metal mixture streak, but it doesn't show well in all the photos, if you're talking about that, instead of the discoloration in the field above the date.
@Fred Weinberg @Shrews1994 ...Shrews...I like Fred’s call, I was also thinking some kind of roller mark...I think both could remain after the strike...Spark