Pop cans, rat pee and MythBusters. (originally from Comestible Zone)
I watched an episode of MythBusters recently and they obtained
1,000 cans of pop from different mercantile establishments in SF.
Jamie and the other fellow wanted to see how many of those randomly purchased
pop cans had rat pee drops on them using UV light to reveal them.
They were shocked by the results, so was I.
Next time I'm in San Fran I will wash off all cans of pop I may purchase there.