Filthy Rich Businesses Want to be disgustingly happy? Start a disgusting business.

Jay Villemarette cleans skeletons--mostly animal and human skulls--for a living. He owns Skulls Unlimited International and insists there's never a dull moment at the office. We'll take his word for it. After all, his company might be cleaning a gorilla skull one day and that of a chipmunk, a giraffe or a human the next.

But that doesn't mean he finds all the company's projects pleasant. "We don't like working on humans," concedes the 41-year-old entrepreneur. "As a whole, we'd rather not do it." Is that because it's morbid and sad and gross?

"No, that's not it," says Villemarette. "They're just bones. It doesn't bother us that they're human. But humans are really greasy because of what we eat, like Doritos and burgers. We've worked on lots of body parts, and they all seem to have the same smell. But humans, like bears, have their own distinct odor." Not an odor of death, Villemarette elaborates, but more like something that has spoiled in the pantry. While his company might charge in the neighborhood of $7,500 to clean a human skeleton, a bear skeleton--even with its distinct odor--would cost much less.

Revolting. Disgusting. Messy. Repellent. Repulsive. Whichever word you use to describe some businesses, there's something that many of the least glamorous industries--think sewage, garbage, skulls--have in common. They're almost always important to society, and they're frequently industries that can make an entrepreneur very wealthy. But even more surprising?

These entrepreneurs are happy. In fact, they may be happier than you are.

At first glance, you might look at Skulls Unlimited International in Oklahoma City, probably one of the only businesses in the world that specializes in cleaning human and animal skulls, and think, "Gee, I wish it were limited. Why would anyone want a skull, no matter how clean it is?" But museums, veterinary and medical schools, and other educational groups might take umbrage with that assessment. There are enough of these establishments, in fact, that Villemarette needs 13 full-time staffers and two part-timers and expects his company to break $2 million in sales this year. And it all began when he found a dog's skull in the woods at age seven. Later, after finding a cat skull, he began studying the similarities, having been bitten by the biology bug. He soon became a self-proclaimed skull junkie.

He admits it's an unusual career: "My wife used to cry herself to sleep at night because her husband was starting a business in cleaning skulls," says Villemarette, joking. At least, we think he's joking. In any case, his wife isn't crying now, and Villemarette is as happy as a clam skull would be--if clams had skulls.

Mike Rowe, the host of Dirty Jobs on the Discovery Channel, says that Villemarette's attitude isn't uncommon. Rowe, who has featured Skulls Unlimited on his series, has met many entrepreneurs and employees in dirty jobs, and they've made quite an impression on him, especially when he sees how happy these people often are, even those clinging to the lowest rung on the ladder. In fact, there's a lot that entrepreneurs can learn from the employees who do the most back-breaking, disgusting, dirty sort of work.

"Most of the people I've met on this gig are happier, more adjusted and balanced than anyone else I've met," says Rowe, who thinks that's partially because the jobs typically begin and end within a predictable period of time. "You end up living a more balanced life. When you go home, you aren't taking your work home with you."

In addition to hosting the show, Rowe speaks to Fortune 500 companies about the differences between their jobs and dirty jobs. "There's a ton of truth in the fact that a ditch digger can look down at their ditch and say, 'There's my ditch. It wasn't there this morning, and now it's done,' while a lot of quote successful people look at their desk at the end of the day, and it looks the same as it did in the morning," he says. "That'll wear you out after awhile."

Finding Pleasure in the Putrid
That may be why Robert Weitz, a co-owner of RTK Environmental Group in Stamford, Connecticut, enjoys his business, which tests for mold, lead, asbestos and indoor air quality, so much. He does have a desk, plenty of paperwork to parse through and numbers to crunch, but he also frequently--generally five to six times a week--gets out into the field. And it's never dull.

"We never know day to day what we might walk into," says Weitz, who is 48 and built houses before immersing himself in what wears homes down. "We have an address and a town, and that's all you know."

He recalls going to a very affluent abode, where the owner promptly gave him a suit to protect his clothing. "I knew I was in trouble at that point," recalls Weitz, who wound up in an 18-inch-high crawl space leading from the closet, where he not only checked out a mold problem but found himself crawling in the dirt, inching past mice corpses, and moving across mole droppings and shards of broken light bulbs. But Weitz considers his situation fortunate. He was just there to take photos and collect information for a remediation company to bid on the project and then actually clean everything up.

Echoing the skull cleaning entrepreneur, Weitz happily admits, "I love what I do. I hear so many people say, 'I hate going to work,' and I think, 'How can you do that?'" Part of the appeal, says Weitz, is knowing that he can help owners with children who have asthma or families that are being exposed to radon, a cancer-causing gas. He also gets to meet a wide spectrum of people, from wealthy CEOs and movie stars to impoverished children in filthy apartments. The latter is tough, but when Weitz is on an assignment like testing for lead in a low-income neighborhood and sees holes in the wallboard from rats in a child's bedroom, he at least knows he's doing something positive for them.

There's also a biological appeal to what he does. "There are so many different types of mold," says Weitz. "It's fascinating. We've identified almost a thousand types in the industry, and that's probably out of hundreds of thousands. The way molds grow is incredible. I know to anyone else, it's disgusting, but to me, it's fascinating."

If nothing else, working in a dirty environment can't help but improve your sense of humor at the workplace. Brian Scudamore, the 36-year-old CEO of 1-800 Junk, a $65 million North American franchise, says that his company holds contests between the truck drivers for "weirdest" junk found. "It actually creates bragging rights," says Scudamore, who himself in the early days of his business removed an unplugged refrigerator full of very bad smelling, rotting salmon. His franchise owners and their employees, meanwhile, have found themselves in a variety of odd situations, including emptying out a mortician's closet and hauling away 18,000 expired cans of sardines.

Cleaning Up--Financially
One reason entrepreneurs may be thriving in dirty jobs is that so few others are doing it, theorizes Rowe, who years ago spent summers between school doing less-than-glamorous work in construction, roofing and grave digging. "There are huge benefits to hopping on the road less traveled," maintains Rowe. "The best opportunities in the world are often in the cracks. Some of the best entrepreneurs I've met began by seizing an opportunity, and obviously you have to look for opportunities where others aren't looking. You aren't going to find them on Main Street."

Rowe cites the emergence of golf ball entrepreneurs who put on scuba gear and swim through "methane-rich mud, blindly, and scoop up these balls with the nets and then sell them for 25 to 70 cents online. I know two of them who, last year, pulled off a million and a half in sales."

Rowe was also impressed by a pig farmer in Las Vegas whom his show profiled. The farmer collects uneaten buffet food for his pigs, which are so well fed, they're bigger than your typical swine. He also loves the story of a man he met who "makes flower pots out of cow crap. It's rich in nutrients and biodegradable, so you plant the whole pot." Rowe explains that the entrepreneur collects the manure from hundreds of cows, dries it out, aerates it and runs it through a system until he has a pot. "He's making a fortune in cow crap," says Rowe. "So basically, to sum it up, you've got cow crap, uneaten buffet food and random golf balls that are yielding people a fortune."

Rowe, and everyone else wading in the mud and muck, have a point. These may be dirty companies, but they're businesses that can make an entrepreneur filthy rich. To paraphrase the expression, it's a dirty job, but somebody's smart enough to do it.