A storage locker in New Jersey has been hiding a stash of art potentially worth millions. As The New York Post reports, New York City art dealer David Killen discovered six paintings inside the unit believed to be authentic Willem de Koonings.

Killen runs the David Killen Gallery in Manhattan's Chelsea neighborhood. He purchased the contents of the locker, consisting of 200 paintings from a late art conservator's studio, for $15,000 in 2017. It wasn't until later when he was sifting through the haul that he came across large boxes labeled "De Kooning." He also found one piece by the early 20th-century modernist painter Paul Klee.

Willem de Kooning died in 1997, and today his abstract expressionist paintings are incredibly valuable. His 1955 piece "Interchange" sold for $300 million at auction in 2015, making it the second most expensive painting ever sold at auction, just behind Leonard da Vinci's "Salvator Mundi."

The six pieces Killen discovered aren't signed, and they haven't been authenticated by the Willem de Kooning Foundation. To find out if he was dealing with the real thing, Killen got in touch with Lawrence Castagna, an art restoration expert who worked for de Kooning. According to him, all six pieces were painted by de Kooning, and they likely date from the 1970s.

De Kooning paintings have a tendency to pop up in unlikely places. In 2015, a couple found a long-lost painting by the artist on a secondhand website and bought it for $500.

[h/t The New York Post]