(someone) could sell sawdust to a lumber mill sentence
A very persuasive salesperson is able to sell products to those who don't need them.
She has the ability to persuade others, so she could sell sawdust to a lumber mill.
You will need to learn from John who could sell sawdust to a lumber mill.
The origin of this phrase is not clear.
Used to refer to a intelligent or smart person
If you're such a clever clogs, beat him in this chess game.