Pat Miller greets her son Kevin Miller as she begins her shift Thursday at their family-run business, the Red Rooster, in Damascus. Someone has been stealing their used cooking oil. (Katherine Frey/THE WASHINGTON POST)

Many tempting things emerge from the Henny Penny Pressure Fryer 500 at Maryland’s landmark Red Rooster restaurant.

But the thief with the head lamp and bolt cutters didn’t stop by the Damascus dive for the lovingly crisped drumsticks. At 3:07 one morning last week, he backed up a tanker and vacuumed out the rancid canola oil from the dumpster outside. (Think old Valvoline, but with seething bacteria and ripples of fat.)

“That would be about the last thing I’d want from here is their used grease,” said Bobby Hubble, a construction worker who has been stopping at this cramped Damascus restaurant for decades and is partial to the juicy two-piece chicken plate, with coleslaw, fries and a dinner roll.

But for iron-stomached criminals, the greasy dregs translate to easy cash. Demand is high for recycled oil. Once treated, “yellow grease,” which can net $3 per gallon, is used to fuel biodiesel fleets and as a key ingredient for feeding poultry in Delmarva and pigs in China.

Fairfax County had eight oil-theft reports in an eight-day stretch this month. In recent weeks, JW and Friends, a Springfield pub, was hit. So was Hunan Chinese Gourmet at the Fair Oaks Mall. “It seems like free money for the people going around doing it,” said Lisa Bromley, a Montgomery County police officer who has tracked dozens of reports since February.

One industry group, the National Renderers Association, estimates that 190 million pounds of used cooking oil — about 25 million gallons — is stolen each year. For comparison, the Exxon Valdez spilled about 11 million gallons of crude oil into Alaska’s Prince William Sound.

Valley Proteins, the Winchester, Va.-based recycler that has been carting away Red Rooster’s used oil for years, buys about 5,000 padlocks every three months to lock down oil dumpsters, according to James Katsias, the company’s assistant director of procurement.

“We’ve lost that many to snips and cuts and everything else. Torches. You wouldn’t believe people actually break into the tanks with small torches as well. They cut through the grates,” Katsias said.

Others are more cunning. Someone impersonated Valley Proteins to try to steal old oil from the District’s Old Ebbitt Grill, he said.

Kevin and Pat Miller, the son-and-mother team who run the Rooster, tallied losses of several hundred dollars from a pair of thefts captured on surveillance video.

“It just makes you mad, because you work so hard to make something good,” Pat Miller said, standing alongside an iron rooster, a rooster cookie jar, a rooster clock, rooster curtains and three clay roosters resting on a Coke machine beside a pair of American flags — garage-sale tokens from loyal customers.

When Pat Miller and her husband, Pete, were asked by a local businessman to run the Rooster more than 30 years ago, they didn’t know whether they could do it. “Talk about scared. Oh, my God,” Pat said.

After losing her job as manager of a doughnut shop, Pat had been working at a nursery, watering plants. Pete had run a Chevron station, a Radio Shack and a small engine-repair shop. “Coming into something like this, it’s a little different, a different kind of grease,” Pat said.

As rural northern Montgomery County added swaths of new homes, and as traffic snarls crept down roads and into small-town life, the Millers kept frying. Now on a typical Mother’s Day, they might sell 7,000 pieces of chicken: $7.81 for six, or $117 for 100.

For years, the Millers, like many owners of small restaurants, paid to have their grease hauled away. Then they started getting modest payments, maybe $25 a month. But as feed makers and biodiesel plants have competed for raw materials, more restaurateurs — and criminals — have realized the value of what’s sitting outside. This year, a Pennsylvania recycler offered the Millers $160 for every full dumpster.

While renegotiating their contract with Valley Proteins, their longtime collector, a salesman noticed wild fluctuations in the Millers’ monthly totals. Surveillance cameras provided the confirmation: They were being robbed.

“I have three kids I’m trying to support,” Kevin Miller said. “They might as well have cut the lock on the door and come in and taken $200 from the register. It’s the same thing.”

Kevin started working full time in the family business when he turned 18. That was 24 years ago. He shows up at 4:30 a.m. to break down and sanitize the ice-cream maker and prep for his breakfast regulars.

He loves the regulars’ company and, most of the time, their food. One customer special orders tuna sandwiches with bacon, fried onions, barbecue sauce and pickles. He makes it all, menu or not. But still. “Nasty,” Kevin said.

But not as nasty as the sour blackened byproduct from weeks of fried deliciousness.

It begins with a fresh box of canola oil in the Rooster’s kitchen. It bubbles and sizzles at 350 degrees for a week before the Rooster crew dumps it into a white plastic pickle bin and lugs it outside. Bacon grease and charbroiled burger fat are scraped in as well. The elements and assorted microorganisms help feed the nauseating transformation.

“It gets pretty rank, let me tell you,” Pat Miller says. “Can you imagine stealing that?”

The soupy mixture is supposed to be picked up by a driver for Valley Proteins, where workers would cook it and spin it through a centrifuge at 40,000 revolutions per minute to remove the solids. The cleaned-up grease would go to bind ingredients in livestock feed — like butter in a cookie, the company says — which all leads, eventually, to more fried chicken.

Where the Rooster’s stolen goods are going remains unclear.

Katsias, the oil procurement executive, thinks much of the pilfered oil is purchased by other recyclers hungry for supply and disinclined to ask too many questions.

Montgomery police say some stolen oil has been shipped up the East Coast. A patrol officer stopped a couple of men in a New York-bound tanker months ago but had no evidence of a crime and let them go. Police also suspect some moonlighting.

“Those trucks aren’t cheap. It’s not like someone decided, ‘Woo! Let’s go get some cooking oil.’ It’s a little more organized,” said Bromley, the Montgomery officer.

In Fairfax, investigators are eying a range of possible offenders. “These people may be dealers working in networks, or they may be entrepreneurs working . . . in their basements,” said Lucy H. Caldwell, a police spokeswoman.

Arlington County police made an oil bust at Ballston Common Mall last year, and Fa De Zheng of Oxon Hill, accused of grand larceny, is awaiting trial.

The man seen cutting the dumpster locks in Red Rooster’s surveillance video seemed at ease. He emptied the containers in less than two minutes, then calmly replaced the lids.

“I’d like to see them get caught,” Kevin Miller said. “The person doing it needs to find a job other than stealing my grease.”