Elevator buttons and keyboards are teeming with bacteria, and you don’t even want to know what might be lingering on the coffee mug you keep at work. TIME rounded up the five germiest places in the average office, and you’ll probably want to wash your hands after reading it.
Disposable coffee cups are perhaps the most surprising one mentioned. One 1997 study found coliform bacteria (a.k.a. fecal matter) on 20 percent of the cups and lids tested. And those sponges in your office kitchen? They’re absolutely filthy. After the same researchers used a communal sponge or rag to wipe down the coffee cups, 100 percent of them tested positive for fecal bacteria. If lugging your cup to and from the office in order to wash it at home seems tedious, one of the researchers recommended investing in a personal cup washer to keep at work. As TIME notes, disposable coffee cups are also problematic because someone may pick up a couple lids that are stuck together, then return the now-contaminated lids for other, unsuspecting coworkers to use.
Unsurprisingly, objects that people regularly interact with—such as elevator buttons, office doors, and conference room phones—also made TIME’s list. Anything that’s frequently touched and seldom cleaned is a cause for concern because it could carry microbes that make people sick. If you're a frequent business traveler, for instance, you should wash your hands and wipe down your phone after going through airport security. Those plastic bins you stick your shoes, electronics, and personal items inside are germ-infested cesspools.
Another study from 2014 swabbed 120 elevator buttons at three hospitals in Toronto, Ontario. While the study wasn't conducted in an office building, the results were still telling. Researchers discovered that 61 percent of the buttons contained bacteria, compared to only 43 percent of toilets. This is likely due to the fact that toilets are often cleaned more frequently than elevator buttons. The most common type of bacteria found were Coagulase-negative staphylococci (CoNS), which can be a risk factor for diseases for people with an already compromised immune system or those who have recently undergone certain surgeries or medical procedures.
Lastly, you’ll want to wipe your keyboard and mouse with a disinfectant wipe as often as possible. It might just save you from having to use up your sick days.