Error coins have been a favorite collectible for many years. These are coins or bills that are made incorrectly using the wrong blanks, off-center strikes or strange inclusions. A Roosevelt dime struck on a zinc-coated sixpenny nail was sold in January 2016 by Heritage Auctions. Sold for $42,300, it is perhaps the strangest known “error coin.” It reminds us of the strangest “retained obstruction” error bill, a $20 Federal Reserve Note with a Del Monte banana sticker stuck to it before it was completely printed. The printing covers the paper and the banana sticker. It sold for $10,100 in 2003, then resold in 2006 for $25,300.