$500 for filthiest subway pic

There’s gold in those piles of subway trash.

Transport Workers Union Local 100 is looking for photos of disgusting, trash-ridden New York City subway cars, urging riders to send in their nastiest images through Nov. 30 — and promises the winner will get a $500 check.

The contest was announced Monday amid bitter contract negotiations between the union and the Metropolitan Transportation Authority. The two sides have been without a collective bargaining agreement since May 15.

Local 100, which represents some 40,000 New York City transit workers, alleged online that the MTA has failed to replace 79 train car cleaners who have left.

“It’s disgusting!” the union wrote on the contest’s website, TrashTrain.net. “If you encounter a filthy subway car, it’s because the MTA doesn’t have the staff to clean it.”

MTA spokesman Tim Minton said the agency will not negotiate with the union in the press, but assured riders that subway cars are regularly washed.

“All 591 MTA subway trains in service every day — more than 5,000 train cars — are routinely cleaned multiple times throughout the day,” said Minton. “NYC Transit mobile wash teams and daily cleaning staff are deployed to all 473 NYC Transit stations to address platforms.”

Union officials had already uploaded a batch of nasty photos to the contest’s website Monday morning, including images of train cars covered in feces, garbage and puddles of urine.

Local 100 said it won’t accept images that contain faces of workers or riders, but noted that they will use the submitted images in their “campaign or in union ads or flyers.”