SALT & PEPPER

A few Mensa members were dining at a local cafe. They found the saltshaker contained pepper and the pepper shaker salt.

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 then wanted to demonstrate their brilliant solution to the
attractive blonde waitress and impress her.

They said to her, introducing the subject, "We couldn't help but notice
that the pepper shaker contains salt and the salt shaker pepper..."

"Oh, sorry about that." She cut them short, simply unscrewed the caps of both bottles and switched them.