Your belly button -- like the rest of your body -- needs cleaning.

In 2011, scientists at North Carolina State University sampled the contents of belly buttons. Participants were asked to turn cotton swabs in their navels three times, then researchers placed the swabs in vials. After they allowed the bacteria to grow, researchers took photos of the multiplied bacteria and placed the images online. The gunk-filled images conveyed to participants that belly buttons need regular cleaning.

Regular Cleaning Required

Unwashed belly buttons contain bacteria, fungi, yeast and mold. To keep things clean in there, wash your belly button with soap and water every time you bathe. A cotton swab may make the process easier, but a wash cloth or your fingers also work, as long as they are clean. There's no need for constant navel cleaning, however. Nearly all the bacteria on your skin -- including in your belly button -- is good bacteria, meaning it does you no harm.