Cartoon dad Homer Simpson once came up with a brilliant plan for making a quick buck.
His scheme? Stealing smelly, dirty, used kitchen grease and re-selling it for profit.
Now, with average gas prices topping $4 a gallon, it seems life is imitating cartoon.
That's because frying oil can be used to make bio-diesel, an alternative fuel that can power cars and other vehicles that driven by a diesel motor.
Only two years ago, discarded grease was sold for roughly 75 cents a gallon on the commodities market. Since then, the price has more than tripled to $2.60 a gallon.
With the gooey stuff now being something akin to liquid gold, restaurants in states from California to Florida are reporting a rise in used-grease thefts.
Nick Flores, the manager at La Pinata, a Mexican restaurant in Alameda, Calif., that serves hundreds of baskets of deep-fried golden tortilla chips each day, says he was shocked when his bins of used oil were hit by thieves.
"Grease stealing?" Flores told ABC News. "[That] would never have crossed my mind, no way."
La Pinata, which goes through about 200 gallons of vegetable oil a week and keeps its bins of discarded grease out back, used to have to pay about $160 a month to have someone haul the oil away.
Now a collection company, Blue Sky Biofuels, comes and takes the grease for free. But by the time they get to the restaurant, its operators often find the slick bins empty.
"They steal stuff that's valuable," Flores said of the thieves who steal his grease.
Amateur chemists can turn cooking oil into bio-fuel with the help of a simple conversion kit that can be bought new online for anywhere from $1,000 to $3,000. A favorite with environmental enthusiasts for years, the process has now become a hit with people ranging from small-time entrepreneurs to drivers squeezed by sky-high gas prices.
Truth be told, Flores doesn't seem too bothered by the stealth operators who take his grease in the night.
"I mean, we are just so glad we don't have to pay for it," Flores said.
But others say stealing grease isn't a victimless crime. The thefts have a significant impact on contractors who are paid to collect cooking oil for bio-diesel conversion.
Ralph McIntyre, a grease-hauler from Sky Blue Biofuels who services La Pinata, has resorted to putting heavy padlocks on his oil drums to keep out unwanted profiteers.
"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," said McIntyre, wearing blue plastic gloves as he unlocked a heavy drum containing about a week's worth of La Pinata's used vegetable oil.
"It costs me dollars to get manpower out here to collect the oil," he said. "And then I also have consumers that are counting on this oil. ... Thus, it hurts me in both ways."
McIntyre's truck can hold up to 1,200 gallons of discarded grease and McIntyre says his pickups can sometimes fill it twice in one day. With bio-diesel selling for about $4.25 a gallon, that means on a good day his efforts can net the company around $8,000 in grease profits.
And with those kinds of prices, it seems neither McIntyre, nor the bandits who would have his grease, mind the more unpleasant sides of their business -- most strikingly the grease's pungent, rancid smell.
"Yeah, a lot of people say it stinks," McIntyre said. "But around our facility, I'll say it smells like money."