Excellent article on how counterfeit detector pens work.
The pens detect the starch content in money. Regular paper has starch, currency paper doesn't.
Magician and skeptic James Randi uses an ironing product, spray starch, that makes genuine bills appear counterfeit. Then he returns the starched bills to the bank. Eventually someone will attempt to pass the genuine but starched bill, leading to police, siezed money, etc.
3,500 Fitzwilliam Museum (Cambridge) coins harvested into Nomisma - Using a combination of the University of Cambridge Fitzwilliam Museum's API to query for Roman Republican and Alexander the Great coins and PHP-based scree...
1 day ago