The column for January 16, 2015 states when discussing U.S. bills: “Don’t get too excited, though: these amounts are so small that no one’s getting high off the U.S. Mint’s supply.”
Paper currency is not manufactured by the U.S. Mint, but rather by the U.S. Bureau of Printing and Engraving. Both coins from the Mint and bills from Bureau of Printing and Engraving are not legal tender until put into circulation by the Federal Reserve Bank.
Of course Cecil knew this, it just slipped his mind.