Grease recyclers who collect the stuff say that supply is down anyway because the economic slump is keeping more people at home. Thefts mean grease can be really hard to find.
Used grease can be recycled into biodiesel fuel.
Aaron Perry, chief executive officer of Rocky Mountain Sustainable Enterprises in Boulder, Colo., told The Denver Post that thefts appear to have doubled in the past year. The company collects grease from many restaurants in the Boulder and Denver areas.
Peter Meersman, president of the Colorado Restaurant Association, said that he has had no complaints from his members of grease thefts. But DeWayne Perry, Aaron's father, said that is not surprising.
"It's kind of the equivalent of someone stealing your garbage -- it doesn't register very high on your radar," he said.
2014: The Year in Music [PHOTOS]