Politicians in Washington hardly let a few minutes go by without mentioning how broke the government is. So, it's a little surprising that they've created a stash of more than $1 billion that almost no one wants. Unused dollar coins have been quietly piling up in Federal Reserve vaults in breathtaking numbers, thanks to a government program that has required their production since 2007. And even though the neglected mountain of money recently grew past the $1 billion mark, the U.S. Mint will keep making more and more of the coins under a congressional mandate. The pile of idle...