No one intends to spill drinks like coffee or milk in their car, but it happens every day. When a spill does occur, it's best to clean up the excess liquid immediately using paper towels or a clean cloth. Don't let it set.
No one plans for his or her car to stink, but stink happens. Sometimes it sneaks up on you, like a car's musty smell that builds after months in a damp garage. Sometimes it hits you in the face with the stench of a rotting, dead animal — because sometimes, the source of the smell is a rotting, dead animal.
A stinky car is bad for obvious reasons, but a stubborn stench can have effects that go beyond the immediate olfactory offense. It could actually reduce the resale value of your vehicle. And because your auto is a sealed environment that is frequently pressurized by its own HVAC system and left to bake out in the sun, the bad smells won't just go away on their own. In fact, they tend to get worse over time. Remember the "Seinfeld" episode in which his BMW was possessed by the aberrant body odor of a parking valet? Jerry was willing to give his German masterpiece away for nothing, simply to rid himself of the overpowering odor that seemed to infect everyone who came in contact with it.
What's Causing That Smell?
According to Kenneth S. Suslick, a chemistry professor at the University of Illinois at Urbana-Champaign who has written extensively about the chemistry of scent, humans perceive aromas through an array of millions of cells in the nasal cavity called the olfactory epithelium. The receptors of the olfactory epithelium bind to various airborne chemicals and fire neurons to communicate smell to the brain. Different sections of the olfactory epithelium are tuned to receive different types of odors, and the way we tell one scent from another is by the pattern of receptors that are triggered — complex ones trigger a variety of neurons that blend like dabs of color on a canvas.
Watch Video: How to Remove Cigarette Odors from Your Car
"The olfactory system evolved primarily to keep animals away from concentrations of bacteria," Suslick says. "We're most repulsed by gases that are produced as byproducts of these microorganisms." These gases can include amines (the ammonia smell of urine), hydrogen sulfide (rotten eggs), butyric acid (vomit, rotten milk), putrescine and cadaverine (rotting flesh). "There's really no way to stop bacteria from releasing these gases," he says. "They aren't under the control of the EPA, and they don't respect the Clean Air Act."
Other smells, such as smoke, skunk, mildew and fuel, are not the direct byproducts of bacteria, but can be especially difficult to eradicate because they permeate the entire vehicle — getting into the HVAC system and settling in all the fabrics of the car. Diane Barnes, president of a bioremediation and cleanup company called BioWorld Products in Visalia, Calif., has seen her share of customers afflicted with terrible automotive stink. "We've had people cry because of a smell," she says, "especially with a brand-new car. That's just heartbreaking."
Read: Is That 'New Car Smell' Harming You?
What's the First Step?
Cory Chalmers, owner of California-based Crime Scene Steri-Clean, has cleaned up cars after suicides, police pursuits, accidents and other messy situations. It may seem obvious, he says, but the most important thing when you're dealing with odor is to find the source and clean it up as soon as possible.
That's not always as easy as you might imagine. "We had a woman who left a whole chicken in her trunk and went away for a week while it baked in her car," Chalmers recalls. "We had to tear out the carpeting and get underneath to find where all the fluids leaked."
Chalmers warns that if something stinky finds its way through your carpeting, you're in for a lot more trouble, since there are plenty of holes under the vehicle floorboards, and plenty of places where organic matter can collect and fester. "Spilled milk, for instance, is a tough one," he says. "It will instantly find the lowest point in your car." He warns that if a spill soaks into the floorboards of your vehicle, you're going to want to hire a pro who can locate all the places in your vehicle where smells can hide.
To prevent things from getting to that point, many of the experts we've spoken to recommend keeping a towel handy in the vehicle at all times to soak up spills when they happen. "Dry it up as fast as possible before it sets," says Jon Farmer, general manager of Dakota Products, a maker of environmentally friendly cleaning supplies in Sioux Falls, S.D. For deep-set stinky stains, he recommends an enzyme-based cleaner, which breaks down and digests odor-causing stains.
For really stubborn smells, however, experts suggest a fogger that gets into every surface and crevice where the odors are hiding.
What About a Stubborn Stench?
Some nasty bouquets don't go away without a fight. And most experts agree that perfumes, most deodorizers and pine tree car fresheners are essentially just cover-ups that mask the unpleasantness temporarily.
Many car detailers, deep cleaners and used-car salesmen swear by ozone generators, which produce unstable oxygen molecules that react with odor molecules and destroy them. The problem is that ozone also reacts with just about everything else. "It will hasten the aging of just about every plastic piece in your car," Suslick says.
The Environmental Protection Agency's rap sheet on ozone lists it as a respiratory irritant that can exacerbate asthma and increase susceptibility to lung infections if inhaled in high concentrations. The EPA even calls into question ozone's effectiveness in eliminating odors. Whatever the case, gaseous ozone has a half-life of around 20 minutes, so it's advised that you stay out of any vehicle being treated with ozone, then let it air out for around a half-hour before entering.
If you aren't willing to try ozone, there are a variety of odor neutralizers on the market that chemically bond to odor molecules and prevent them from interacting with the receptors in your nasal passages, working as a sort of olfactory antagonist. Some of these are sold as sprays, but for pervasive smells experts suggest a fogger that gets into every surface and crevice where the odors are hiding. "For smells such as smoke, we recommend a fogger," says BioWorld's Barnes. "A fogger mimics the way smoke permeates a vehicle."
Dakota Products sells a canned product called Odor Bomb ($7) that can fog up an entire car (in fact, it's designed to destinkify an entire hotel room). For more serious or recurring smells, BioWorld sells a small fogger machine for $136 that comes with a liter of concentrated solution to eliminate odor in a small environment such as a car.
Then again, to get rid of a simple, localized stink, there's always Febreze. The main ingredient in this popular spray is called cyclodextrin, which Suslick says reacts in a similar fashion to industrial odor neutralizers, with a slightly different chemical structure. "Think of it like an overgrown donut," Suslick says. Cyclodextrin's donut-shaped molecules tend to surround molecules of smelly substances, immobilizing them and weighing them down until they are essentially dust.
Whatever solution you use, the final step is to let your vehicle air out afterwards in a dry environment. Many cleaners are liquid-based and can remain damp inside an enclosed cabin. If, after all of this, the stink remains, that means it has permeated the fabric and possibly the foam of your vehicle. At that point you may want to start saving up for some new upholstery — or a new car. No one wants to drive around in a big rolling stink.
Visit MSN Autos' "Exhaust Notes" blog to keep up on all things automotive.
Sam Foley is a Connecticut-based automotive journalist who has written for GQ, Forbes, USAToday, theNewYork Post and various other publications.
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