The high cost of producing the lowly penny—about 1.6 cents each in 2014—has led the U.S. government to look unsuccessfully for possible cost savings using different metals. Currently 97.5% of every penny is zinc, a material for which supplies have been shrinking and prices rising.

But "no alternative metal compound would lower the cost of the penny [to less than one cent]," said Tom Jurkowsky, a spokesman for the U.S. Mint.

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