Oh Lisa....never grow up
I have some of those smashed pennies and hope to get around to making something out of them and don't worry about going to prison. The posted info missed a few things.
In the United States, U.S. Code Title 18, Chapter 17, Section 331 prohibits "the mutilation, diminution and falsification of United States coinage." The foregoing statute, however, does not prohibit the mutilation of coins, if the mutilated coins are not used fraudulently, i.e., with the intention of creating counterfeit coinage or profiting from the base metal (the pre-1982 copper U.S. cent which, as of 2010, is worth more than one cent in the United States). Because elongated coins are made mainly as souvenirs, mutilation for this purpose is legal.