I have a number of these lincoln pennies. It's hard to notice on these scans but almost all of the pennies have dark spots. They look gray or dark gray but are only noticeable under certain light. A couple questions: What causes these spots and can they be removed or should they be removed?( I know,many questions in one) Do they hurt the value of the coin? and finally, How much are they worth? They seem to me, spots withstanding, to be at least AU-50, although, the person I purchased them from said they were uncirculated. They do not exhibit the wear of circulated coins but seem to be lightly struck. Let me know what you think, please. Added closer photos.
First the amount of wear on them prevents them from an UNC grade, and your assessment of AU is a good one, IMO. Secondly, the spots may not come off very easy and I would suggest leaving them as is. As far as value, about $.15-$.25.
'60-D sm date cents are distressingly common. Back in 1999 they listed lower than any other BU cent roll at 60c. They are nearly as common now as they were then. Much of the problem is that there were millions saved but the bigger problem is that there is not a lot of demand for them since many collectors don't seek varieties. There are varieties of the small date that are very desirable and these are keepable in high grade like MS-66 and higher. The date comes nice so MS-65 aren't difficult.