Stores around the U.S. are struggling with an unexpected shortage. (No, not toilet paper — sorry, we’ve already made that joke.) They’re running low on coins.

Supermarkets and gas stations across the U.S. are asking shoppers to pay with a card or produce exact change when possible. Walmart has converted some of its self-checkout registers to accept only plastic. Kroger is offering to load change that would normally involve coins onto loyalty cards. Some Wawa gas stations are accepting coin rolls in exchange for bills.

The trouble began weeks ago, when the coronavirus pandemic delivered a bizarre double blow to the U.S. supply of quarters, dimes, nickels and even pennies. Social distancing and other safety measures slowed production of coins at the U.S. Mint. But also fewer coins made their way from customers to banks, coin-sorting kiosks and stores’ cash registers as people holed up at home.

“The flow of coins through the economy … kind of stopped,” Federal Reserve Chair Jerome Powell told lawmakers in June.

That month, the Fed began rationing coins. Soon after, business groups — representing grocers, convenience stores, retailers, gas station operators and others — wrote to Powell and Treasury Secretary Steven Mnuchin that the situation was an emergency.

“We were alarmed to hear that the system for distributing coins throughout the country is at the breaking point,” they wrote on June 23, offering a series of suggestions for how to fix it. A week later, the Fed announced it would convene a U.S. Coin Task Force to address the matter.

“Like most retailers, we’re experiencing the [effects] of the nationwide coin shortage,” a Walmart spokesperson wrote to NPR on Thursday. “We’re asking customers to pay with card or use correct change when possible if they need to pay with cash. Cash is welcome at all of our stores.”

A CVS representative said the company is “encouraging customers, if possible, to pay for their purchases using exact cash, credit/debit card or check” and is working with banks to “minimize impact to our customers.”

“Like many retailers and businesses, we are adjusting to the temporary shortage in several ways while still accepting cash,” a Kroger spokesperson said in a statement, outlining various options customers are now offered instead of coin change.

One of those options — at both Kroger and Wawa — is to round up shoppers’ amounts to donate to charity.