UHIb GM

Opting for the plastic or paper cups set out by a hotel may keep you safer in the long run. In fact, one investigation reveals that some hotels clean off the glasses using the same towels or sponges they used to clean the floors.

Think that pot of coffee you brewed is fresh? The life forms multiplying within its reservoir and drip tray tell a different story. A study of hotel coffee makers published in Scientific Reports reveals up to 67 different types of bacteria lurking within.

A shocking amount of our leftover hotel toiletries—two million bars of used soap in the United States alone, for example—are thrown into landfills on a daily basis. If you want to help out, either finish up that bar at home, or see if the hotel you're staying in has partnered with Clean the World, an organization that safely recycles unused toiletries has distributed more than 44 million bars of soap to people in need in 127 countries. And when you want to make your next trip more enjoyable, learn the 30 Secrets Only Airport Insiders Know.

If you're budget-conscious, avoid that mini-bar like the plague. Research from Priceonomics reveals that mini-bar food and drinks are often marked up nearly 400%. And before you embarrass yourself abroad, practice the 20 Country Names You're Mispronouncing.

Unfortunately, in many cases, the methods used to clean hotels are just making contamination worse. Research published in Food and Environmental Virology reveals that certain cleaning methods actually increased the spread of viruses throughout a hotel.

Think your premier suite at a five-star hotel has five-star cleanliness? Think again. In fact, a study conducted by Travelmath found that four- and five-star hotels actually packed significantly more bacteria than their three-star counterparts.

Unfortunately, that standard bathtub isn't much better. Considering that research suggests that hotel housekeepers' sponges are among the dirtiest items in the hotel, the bathtub they just cleaned with one is likely teeming with bacteria, too

That hotel whirlpool tub but may be relaxing—until you find out what's actually in it, that is. According to research from Texas A&M University, 95 percent of whirlpool tubs had fecal-derived bacteria, 81 percent contained fungi, and 34 percent had staphylococcus bacteria—the stuff that causes Staph infections—in them. For more great travel advice, check out the 10 Best Winter Weekend Escapes.

That "Do Not Disturb" sign on your door is a suggestion, but not a binding agreement. A number of hotels have ditched the "Do Not Disturb" signs in recent years, citing security issues, so you should assume that, after 24 hours, housekeeping will enter just to make sure everything is okay. And when you want to make your next vacation a little more exciting, book a trip to one of the 15 Most Haunted Places in America.

Bed bugs are the bane of the hotel industry and a huge fear for your average traveler. Unfortunately, your chances of staying in a hotel where they've been are higher than you might like. In fact, hotels are the third-most-common location for bed bug infestations, according to exterminators, and New York hotels saw a 300 percent jump in bed bug infestations in a single year, according to one report. If you're dealing with the critters in your own home, be sure to check out the 20 Ways to Banish Bed Bugs—For Good.