Bud and Gretchen Weidknecht, who run the Carpenter's Cupboard non-profit, said a woman dropped off an old artist's portfolio that was found to contain a Salvador Dali lithograph from 1977, during the artist's surreal period, The Rocky Mountain News reported Thursday.

Bud Weidknecht described the lithograph as depicting "a bunch of naked guys ascending into heaven."

"It was in the period of time before he went a little screwy," he said.

The Weidknechts said the woman disappeared before they discovered what was inside the portfolio.

"We're a faith-based organization, and we try to play it straight," Bud Weidknecht said of the charity, which accepts donations of food, clothing and other items that are distributed to the needy. "We want to give the lady the option to take it back."