(someone) could sell ice to Eskimos phrase informal
Someone is such a smooth or convincing salesperson that they can sell things to people who don't need or use it.
The salesman was a real fast talker, and somehow managed to convince me to buy an extra car. He could sell ice to Eskimos.
To be cautious; to plan ahead instead of taking a risk
I like to err on the side of caution and always keep some money in my savings account.