KTKA

La Pinata restaurant in San Francisco serves hundreds of baskets of chips a day, and they are all deep fried in vegetable oil.

Restaurants used to have to pay someone to haul away their used grease. Not anymore.

Frying oil can be used to make biodiesel, an alternative fuel, and with the skyrocketing price of gas, that grease has turned into liquid gold.

Two years ago discarded grease sold for roughly 75 cents a gallon. Today the price has more than tripled. Now, people steal it.

Restaurants from California to Kansas are reporting a rise in used oil thefts.

La Pinata's manager Nick Flores was shocked when his bin of used oil was hit.

"Grease stealing? Never have crossed my mind, no way," Flores said.

It wasn't too long ago that such a crime would seem absurd. It was even a joke on an episode of the TV show, The Simpsons.

Stealing smelly grease may appear to be a victimless crime, but the thefts are having a significant impact on contractors like Ralph McIntyre, who are paid to legally collect grease for biodiesel conversion.

"Basically we are having people come by in the middle of the night, and they just lift the lid and suck the oil out for their cars and what not," McIntyre, with Sky-Blue Biodiesel, said.

These days McIntyre puts locks on his bins of slimy, used oil to keep the thieves away.