How to catch an American spy→

BBC News:

The Americans planned these operations meticulously – their agents had Russian clothes, spoke the language like natives and were dropped in with the latest in spy gadgets.
But time after time they were unmasked by the KGB.
With a gleeful smile, Valery tells us why. The staples holding together the agents’ fake Soviet passports were made of good US, non-corrosive, stainless steel.
Genuine Russian passports had staples made of metal that began to rust as soon as the passports were issued.

God I love Cold War stories like this.