If you're referring to the proof coins that are missing the San Francisco mintmark, you should know that they aren't worth much unless they are in the original Mint case. Chris
@Travis G These are Missing Clad Layers.. From my collection - It only occurs on one side of a clad coin. Any side. Yours is just simple Environmental Damage Toning.
@Travis G Don’t let the edges fool you. Occasionally during the blank stamping process, the metal can “smear” giving the appearance that the clad and copper layers aren’t centered or one of the clad layers is thicker or missing. Look at your change for awhile and you’ll see that it’s not unusual.
