Presumably you would sprinkle it on the fake secret documents that you left around for the suspected mole to finger, then you have proof who the mole is. I gue

Presumably you would sprinkle it on the fake secret documents that you left around for the suspected mole to finger, then you have proof who the mole is. I guess these days they just put a dash of Polonium-210 in your tea and follow you with a Gieger counter, sends a much stronger message.