If you’ve stayed in a hotel in the past decade or so, you’ve probably seen a placard over the sink or on the towel rack instructing you, the guest, to hang up your towel if you’re fine with using it again. Sometimes, there’s another little note on the nightstand informing you that fresh linens will be provided daily if you request them, but otherwise they’ll only be changed every couple of days or between guests. The placards say that the hotel has adopted this policy out a concern for the environment; they want to conserve water and power, they say.

Many of my college and post-college roommates had a similar approach to towel and sheet cleaning. Whatever attitude my roommates held towards the merits of conservation, I don’t think that the distinct odor that sometimes emanated from the towels on the rack in our shared bathrooms was due to fanatic Earth love. Nor am I naïve enough to believe that hotels are really all that worried with the water and electricity they waste laundering towels and linens on a daily basis. It’s much more likely that they know that policy can save a boatload of money on maid service and electricity, and you’ll be just fine with that because it gives you that warm, fuzzy feeling inside. Dirty towels are one thing, but a dirty conscience is another thing entirely.

This trend among hotels is an example — albeit a nearly harmless one — of something called “greenwashing.” The term, coined by environmentalist Jay Westerveld in the late 1980s is a good one (he was also discussing hotel towel replacement programs but probably didn’t share my conservation-minded roommate issue). If the term’s meaning strikes you as obvious, it’s because we see greenwashing all the time. “Clean” coal ads have appeared recently in TV and in print, attempting to convince the public that clean coal is possible. And we’ve all watched as BP has added the tagline “Beyond Petroleum” to its name. The company’s extensive marketing campaign might make you think they manufacture bunnies and sunshine, but BP’s profits come from refining crude oil into products that, when used properly, cause global warming.

These are just the most glaring examples of greenwashing, but the practice is sometimes harder to recognize. In last week’s “Green Briefs,” I ragged (perhaps too harshly) on TerraChoice, a Canada-based environmental marketing firm that has partnered with credit card rewards program AIRMiles to offer “greener” rewards choices to its customers. Though I’m still not convinced that the criteria TerraChoice uses to rate the green factor of rewards for the program is all that tough, the company deserves some credit. In 2007, TerraChoice released a study, “The Six Sins of Greenwashing,” in which it evaluated 1,753 environmental claims on 1,018 randomly surveyed common consumer products and found that a whopping 99 percent of the products were guilty of greenwashing. Most products were guilty of the “Sin of the Hidden Trade-Off,” in which products claiming some environmental benefit failed to disclose a potentially damaging trait. Other products committed the “Sin of No Proof,” in which claims of environmental-friendliness could not be verified, and some companies were even found guilty of “Fibbing” – simply lying about environmental claims.

The sheer abundance of products in the consumer market using the “emerald paintbrush” (the clever name of an award given to BP by Greenpeace UK), makes it difficult to know whom to trust, but there are some resources available to consumers worried about being duped. Last month, Newsweek released its first “Green Rankings,” which meticulously evaluated and ranked the environmental achievements and reputation of all the companies in the S&P 500. At the top of the rankings was Hewlett-Packard, which just beat out Dell. Several other technology companies made the top 10, but coffee-pusher Starbucks and chemical company Johnson & Johnson also made it in. Energy companies, including Alabama Power parent Southern Company, anchored the list. GreenwashingIndex.com, a site run by EnviroMedia Social Marketing and the University of Oregon School of Journalism and Communication, takes a crowd-sourcing approach to greenwash watching. The site’s users post ads touting environmental benefits of a product and then rate and comment on the ad’s B.S. factor.

Ethically speaking, it’s difficult to fault a hotel for the towel and linens scheme (I will fault my roommates, however – stinky towels are not ethical). Some greenwashers may be sincerely worried about their environment impact, and the cost savings involved only serve as an added bonus. After all, environmental leaders and politicians (who might themselves be guilty of greenwashing) have for years touted the economic benefits of going green. But when energy companies refer to coal and oil as clean and green, you’ve got to wonder just how stupid they think we are.

Madison Underwood is a contributing writer for Birmingham Weekly. Write to madison@bhamweekly.com.