This is a big bad cud or two on this one, right? How does this happen, and what does it do to the value of the coin..better or worse?
The cud error is caused by a broken die and results in an 'unstruck' area on the coin. What you have is corrosion of the zinc causing the plating to lift.
The rockdude is correct. You have a plating error, not a cud. I can't tell if this is a mint-made defect on your coin, or if it is damage. Either way, its not worth much of a premium.
