Ask the police and they'll tell you that serial numbers seldom help catch thieves -- dedicated crooks are usually smart enough to file off those digits so that stolen items can't be linked to a crime. Researchers at the National Institute of Standards and Technology might have just found a way to recover those numbers and stop criminals in their tracks, however. Their new technique uses electron microscopes to spot damaged crystal patterns in steel, revealing characters even when they've been polished into oblivion. Current recovery approaches (like acid etching or electrolytic polishing) only sometimes work, and frequently provide faint clues at best -- the microscope produces clear evidence that you could use to convict someone in court.
It's going to be a while before the cops are using this method. Right now, it takes three whole days to identify eight numbers. That time could shrink to an hour through optimization, though. If that happens, gun runners and burglars may have a considerably harder time escaping the long arm of the law. Unless nogoodniks get particularly creative, you'd have little trouble tracing many weapons and fenced items back to their sources.
[Image credit: White/NIST]