I found a
Lincoln Cent 1946-S altered to pass as a dime recently.
I checked the local CoinStar machine and saw several coins in the reject bin.
Usually a foreign coin causes the machine to reject coins, buy all 30 of the coins were US pennies,
probably from the same person but I can not be sure.
One had been hammered to nearly the size of a quarter; that one probably caused the rejection.
Of the others, 8 were zinc, 19 were Lincoln Memorial copper, and two were wheat pennies,
a 1956 which had two wire-cutter marks, and this altered 1946-S penny:

The coin was probably altered with a file to pass as a dime in a vending machine.
It weighs 2.67gm, is 19mm in diameter, and the sides are smooth.
I had heard of pennies altered this way but had not seen one until now.
On December 3, 2010 President Obama pardoned a man for doing this "coin mutilation" in 1963.
The man was lucky, in medieval times, the penalty for altering coins was death,
usually inflicted in one of those imaginative ways that medievals had.

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