NEW YORK,-When an American art dealer dropped $15,000 on what he thought was “junk” in a New Jersey storage locker, he never imagined it could be the deal of a lifetime.

But he now believes stashed in the unit were six paintings by Dutch-American abstract master Willem de Kooning, which could be worth millions of dollars.

A de Kooning painting sold for $66.3 million at Christie’s in 2016 in New York, while another sold privately for a reported $300 million in 2015.

Also found in the storage unit, says New York gallery owner David Killen, is a painting by Swiss modernist Paul Klee.

The art originally came from the studio of Orrin Riley, a superstar in the art restoration business who died in 1986, leaving everything to his partner, Susanne Schnitzer, who was killed in a traffic accident in 2009.

Her executors - friends in New Jersey - spent years trying to find rightful owners for the art, but no one came forward to claim the 200 pieces languishing in the storage unit, near the Ho-Ho-Kus township.

“Honestly all I knew was (an)other auction house passed on it, so my feeling was it was a bunch of junk,” Killen told AFP by telephone.

“All these things are boxed up. I said ‘look I’ll give you $15,000 for it. I’ll take a chance,” he said. If nothing else, he thought the items would pad out auctions he holds every two weeks.

It was only once the items were being unloaded that he spotted what he now believes to be de Kooning paintings.

The work is not signed, but Killen said a restorer based on Long Island, who used to work for both Riley and de Kooning, had authenticated the works.

“I can see in his eyes, he’s shaking,” Killen told AFP. “He said ‘this is exactly what de Kooning was doing in the ‘70s, one after the other.”

The New York Post quoted Lawrence Castagna, an art restoration expert based in East Hampton, as confirming the works were by the master.

Castagna did not immediately respond to an AFP request to comment.

Killen believes the paintings could fetch anywhere from $10,000 to $10 million when he offers them for auction later this year and next January.

“I’m excited. Believe it or not - and people will laugh when they hear this - its not about the money. I want some publicity for my auction house,” he said.

But what would he do with a bonanza check? New doors for his gallery and a “really nice apartment,” he replies.

The Post first reported the story on Sunday. Since then, the telephone has been ringing off the hook, he said. “The reaction’s been tremendous.”