You can rule out a mint planchet as the penny was already
stamped both sides. (I'm curious what is under the blue edge)

It seems that someone was playing around with some soet of
a brass erosian chemical to make it look older than it is, and in
the process, ruined the coin - value: 1 cent if you can get it.

Brass erosion can be caused when exposed to dehydrating agents,
such as phosphorus pentoxide or calcium oxide, halogens and
halogen salts, such as bromine and sodium hypochlorite, organic
halides, and acid anhydrides.

The main purpose of people trying to corrode a metal, is to make
it appear to be older than what it actually is.

Al Varelas / USMC
SS-1654
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