[weegee]

I saw something from 1975, don't know if it was an aluminum penny or a plated penny. They were handed out as promotional items at an Offshore Technology Conference.

[JerseyJohn61]

They were probably aluminum plated for novelty
affect.

In 1943, all Lincoln cents that were struck for
release were made of steel because the copper
was needed for the war effort(bombs and bullets).

A few prototypes were struck made of copper but
were not release for circulation. News of these
"copper '43's has had a few generations of folks
going through there pocket change and pennies jars
in search of those elusive cents....JJ61

[endthematrix]

During the early 1970s, the price of copper rose to a point where the penny almost contained more than one cent's worth of copper. This led the Mint to test alternate metals, including aluminum and bronze-clad steel. Aluminum was chosen, and over 1.5 million of these were struck and ready for public release before ultimately being rejected. About a dozen aluminum cents are believed to still be in the hands of collectors,[citation needed] although they are now considered illegal, and are subject to seizure by the Secret Service. One aluminum cent was donated to the Smithsonian Institution.

http://en.wikipedia.org/wiki/Cent_(United_States_coin)