Dumb Blonde Waitress?
How could they swap the contents of the bottles without spilling, and using only the implements at hand? Clearly this was a job for Mensa! The group debated and presented ideas, and finally came up with a brilliant solution involving a napkin, a straw, and an empty saucer. They called the Blond waitress over to dazzle her with their solution.
"Ma'am," they said, "we couldn't help but notice that the pepper shaker contains salt and the salt shaker contains pepper..."
"Oh," the blond waitress interrupted.
"Sorry about that."
She unscrewed the caps of both bottles and switched them!