I noticed while going through a bag of 1960-D BU Lincoln Cents that the coloring ranged from a dull to bright finish; does anyone have any idea why there is so much variance in the coloring?
It depends on the climate conditions. Heat and moisture will have a considerable effect on the coins, especially those nearest the canvas bag. In the 55+ years that the bag has been stored, there is no telling how many different owners had it in their possession under differing conditions. Chris
My guess is the darker brown coins were closer to the air inside the bag and the Red were buried inside the middle of the mass away from the air.