Way back in 1998, in an episode titled “Lard of the Dance,” Homer and Bart Simpson became grease bandits, draining local restaurants of their used fryer oil and reselling it for a profit. Two decades later, folks are still imitating these animated grease grabbers, stealing oil from eateries and selling it to be refined into biodiesel.

Bloomberg Markets explains that we have a 2007 law to thank for the popularity of used vegetable oil. It requires increasing amounts of renewable fuel sources to be used every year. Ethanol, made from corn, is one way to meet this mandate, and turning vegetable oil into fuel is another.

The law accidentally created a black market for old oil. We’ve covered this before, but the prices that people can get for selling it to refiners are increasing. The target for 2017 is 20 billion gallons of biodiesel, making it important for the industry to make sure it scoops up every bit of oil that can be recycled.

“There’s an actual market for stolen oil,” a collector near Buffalo, NY, told a Bloomberg reporter. “It’s almost like a pawn shop or scrap-metal business.”

Trade group the National Renderers Association estimates that $75 million worth of the stuff is stolen across the country every year. What the thieves steal is processed, too, but thefts mean that it isn’t picked up by a licensed collector, and the restaurant doesn’t get anything for its trouble.

Typically, restaurants keep their old grease in locked containers out back, and official collectors pick it up, sell it to refiners, and give the restaurant a cut of the proceeds.

Experts expect oil thefts to increase as the weather improves across the country, so restaurants are installing cameras. Businesses in one area know to look out for an old Pepsi truck that’s loaded with grease.

There’s no word on whether restaurants are still watching for a pink sedan with barrels strapped to it, though.

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