Throughout history, people have used many methods to clean their teeth. Some ancient people chewed on frayed twigs. Others rubbed their teeth with cloth or swabbed them in vinegar. The Egyptians may have been the first people to use toothpaste when they mixed powdered pumice (a porous rock formed in volcanic eruptions) with vinegar and applied it to their teeth in the 100's B.C. Some toothpastes still contain pumice, but science has since supplied other toothpaste ingredients that the ancient Egyptians never dreamed existed.
Biting on aluminum foil can be painful -- basically, when you bite on foil, you build a battery in your mouth. Ouch!
Lance Armstrong, Jose Canseco, Mark McGwire: The list of superstar athletes accused of -- or admitting to -- taking performance-enhancing drugs is almost as impressive as the number of sports that they compete in. And we're not just talking about steroids anymore.