Three roommates who bought a used couch for $20 found $40,000 in cash stashed inside and returned the money to the 91-year-old upstate New York widow who had hidden it there.

WABC-TV in New York City reports that a State University of New York at New Paltz student and his two roommates found the money stuffed in envelopes hidden in the sofa they bought from the Salvation Army in early March.

Reese Werkhoven: 'We pulled it out of the couch and we're shaking and the first thing Lara said is 'lock the doors'.' Photograph: Eyewitness News/ABC

Third-year New Paltz student Reese Werkhoven of New York City says he found the first batch of cash. They searched the couch and found other envelopes stuffed with money.

"We just pulled out envelopes and envelopes," said Cally Guasti, a social worker with Family of Woodstock who shares an apartment with two friends in New Paltz, 75 miles (120 kilometers) north of New York City. "My mouth was literally hanging open everybody's was it was an unfathomable amount."

Guasti told The Associated Press on Thursday that she and her friends had bought the beat-up couch and a chair for $55 at a Salvation Army thrift shop in March. They noticed the arm cushions were weirdly lumpy. Then, one night in April, Werkhoven, opened a zipper on one arm and found an envelope.

It contained $4,000 in bubble-wrapped bills.

Guasti, Werkhoven and roommate Lara Russo opened the other arm zipper and started mining the treasure stashed inside. They counted it up: $40,800.

"We put it all on a bed," Guasti said. "We laid it all out and started counting. And we were screaming. In the morning, our neighbors were like, 'We thought you won the lottery.'"

Later on, Guasti found a deposit slip with a woman's name on it. Werkhoven called her the next morning.

"She said, 'I have a lot of money in that couch and I really need it,'" Guasti said.

They drove to the home of the woman, who turned out to be the elderly woman. She cried in gratitude when they gave her the cash she had hidden away.

The woman's family had donated the couch to the Salvation Army while she was having health problems.

Guasti said the three had considered the option of keeping the money, but decided they couldn't do that.

"At the end of the day, it wasn't ours," Guasti said. "I think if any of us had used it, it would have felt really wrong."