MacGyver and Maxwell Smart had a plethora of tricks up their sleeves (or shoes, as it were), but they never had this. One Paul Kelly and colleagues at Loughborough University have discovered that a disulfur dinitride polymer can not only turn exposed fingerprints brown as it creates a reaction with the nearly undetectable residues, but it can also lift text from departed letters. In an odd twist of fate, it was found that traces of ink jet printer ink can actually initiate the polymer just like print residue can, and the detection limit is so low that details from a letter that was once within an envelope can be seen after adequate exposure to the chemical. And you thought snail-mailing those interoffice love letters was a safe bet.