Need Help with Error (?) . 1959P Jefferson Nickel

I have a friend whose reached out to me for a question about this 1959 Nickel, possible Error ? What causes this ? Thanks in Advance !

 

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Possibility a strike through but it could be just damage,chemical reaction e.t.c

 

I was thinking some type of Die Error ?

 

Grease?

 

Debris filled die. JMHO

 

Thanks ! That was my other choice .

 

Debris or maybe rust.

 

This "rash" is most likely the result of die deterioration as I have seen other, similarly affected nickels.