Bacteria at Your Fingertips explains that “the gunk in your keyboard could kill you”:
A study conducted by Charles Gerba, a professor of environmental microbiology at the University of Arizona, concluded that the computer keyboard was the fifth most germ-contaminated spot in an office. (Topped only by your phone, your desktop — home to an impressive 10 million bacteria — and the handles on the office water fountain and microwave door.) Out of 12 surfaces studied the toilet seat came in cleanest, in case you’re wondering where to have your next lunch break.