I have mentioned several times that I am collecting U.S. nickel coins and copper pre-1982 pennies because the value of the physical base metals from which they are formed (i.e., the "melt value") exceeds their respective face values. Back on December 14, 2006, I mentioned that the metal value of pre-1982 pennies was 2.0752 cents (207.52% of face value), post-1982 zinc pennies had a metal value of 1.1257 cents (112.57% of face value), and nickels had a metal value of 6.9879 cents (139.75% of face value).
The value of zinc (the primary component of post-1982 pennies) has decreased about 13% since then. However, the values of raw copper and nickel metal have risen substantially since mid-December, with copper increasing about 22% and nickel increasing almost 49%. These metals have been soaring during the U.S. commodities boom that has been going on during the past several years. The cause of this boom is most likely due to a continuing weak U.S. dollar and rising demand for raw materials from fast-growing emerging markets such as China and India.
As shown in the chart below (taken from Coinflation.com - click on the image for a larger view), the metal value of pre-1982 pennies is now 2.5237 cents (252.37% of face value), post-1982 zinc pennies have a metal value of 0.9953 cents (99.53% of face value), and nickels have a metal value of 9.7226 cents (194.45% of face value).
With the melt values of these metal substantially exceeding the face value for nickels and at about parity with face value for post-1982 pennies, the U.S. Mint is losing many millions of dollars each year by making these coins with their current compositions. As such, it is practically a guarantee that the U.S. Mint will change the base metals of these coins within the next couple years, at which point the current pennies and nickels in circulation will become collectors' items hoarded just like old silver coins were hoarded when the U.S. Mint abandoned the use of silver in its coins.