On today's Planet Money: More on the mountain of dollar coins sitting unused in government vaults.
We talk to self-described 'travel hackers' who use frequent-flier mile credit cards to buy dollar coins and pile up miles.
And we learn that the U.S. Mint — just today! — said it would stop letting people use credit cards to buy the coins.
Money quote from the mint:
The Mint has determined that this policy change is prudent due to ongoing activity by individuals purchasing $1 coins with credit cards, accumulating frequent flyer miles, and then returning coins to local banks.
Also on the show: Why Ecuador loves U.S. dollar coins.

Subscribe to the podcast. Music: Cut Copy's "Light & Music" Find us: Twitter/ Facebook.
Planet Money's Wall-To-Wall Dollar Coin Coverage:
How Frequent Fliers Exploit A Government Program To Get Free Trips
Dollar Coin Loophole Closes For Frequent Fliers
Bill Would Kill Dollar Coin Program
Senators Call Dollar Coin Pileup 'Troubling'
Ecuador Needs Your Dollar Coins : Planet Money
Copyright 2021 NPR. To see more, visit https://www.npr.org.