Professor Charles Gerba of the University of Arizona is very interested in what's growing on your cell phone, and we're not talking about your bill. He's been testing cell phones and finding that, in general, they're riddled with germs and bacteria that can cause skin infections.

In an informal on-the-street test he ran 11 phones through his "germ meter" test, which counted the number of nasties on the phones. Five of the phones failed that test, meaning they had thousands of types of bacteria. Gerba says that isn't necessarily a problem so long as they all come from your own skin. Once you start sharing a cell phone is when things can get ugly.

This isn't the first we've heard of this, so you'd better take some precautions. Take a disinfectant wipe and rub any surface that might come in contact with your skin, making sure you get into the nooks and crannies. But, whatever you do, don't spray it with cleaner: those microscopic electronics inside don't generally like being misted with conductive liquids.

Of course, you could always use an ear piece or BlueTooth headset and keep the cell phone away from your cheeks entirely.