Basically anything. It's capable of cleaning more than your teeth. In fact, it is quite the problem solver. Check out the whole bunch of things it can clean in the gallery below:

Crayon marks on the wall.

Make your faucets shiny and clean.

Whiten piano keys.

Popping a zit..

Coaster marks.

Cleaning headlights:

Make silverware super nice again.

Remove onion scent on your hands.

Make diamonds look shiny.

Remove all the small scratches on your phone's screen.