Is It Okay To Skip Washing Your Coffee Cup?

Few things in an office are as personal as your coffee cup. You might share a desk, you might share an office chair, but your mug is usually yours and yours alone. It can show your personality and, if you skip the scrub brush, your coffee preferences.

Some people like those dark rings. They're marks of work that's been done that day and the coffee that made it possible. Your friends and coworkers might encourage you to scrub out those marks, however. It can't be sanitary to drink out of a dirty mug, after all — right?

But as Dr. Jeffrey Starke, M.D., explained in an interview with The Wall Street Journal, scrubbing your mug might be the worst thing you can do. It all depends on how you drink your coffee and where you scrub and store your mug of choice. Starke is an infectious disease expert at the Baylor College of Medicine in Texas. He's not usually one to advise against cleaning, but when it comes to the office, he says, less can be more.

In the case of personal coffee mugs — not the communal ones kept in the break room cabinets — Starke stresses that most of the germs on and inside the cup belong to the person who uses it (via The Wall Street Journal). Since those germs are already in that person's body, they're not likely to do much harm. Plain coffee isn't likely to mold, either, so it doesn't really add to the germ content of a mug. Cream and sugar, however, will absolutely mold if left unwashed. Using either of those ingredients is an instant must-wash verdict (via The Cut). If you take your coffee black, however, leaving the rings in place isn't going to hurt you. And in some cases, it's safer than washing your mug in the break room.

As Bustle explains, there are some serious germs in the break room. In fact, 90% of communal office mugs are loaded with germs, including fecal matter. These germs are even more prevalent on the shared brushes and sponges used to clean office dishes, meaning that using them on your mug is likely to just replace your coffee rings with foreign microbes. So if you're going to soap up your mug, do yourself a favor and do it at home where your germs are yours and yours alone. If you can't, then your best bet is to take your coffee black and let your mug wear those rings with pride.