Help! My Nails Are Yellow

No I don't have nail fungus. Dark nail polish has made my finger nails yellow. Yuck.

Not my nails, but the color is pretty close.
The stains on my nails are  just on the top third.

The thriftiest and best tip I've come across is from The Doctors (see video here). Take a soft toothbrush and use a circular motion to spread whitening toothpaste on your nails. It really works. Obviously you don't want to use the toothbrush that goes in your mouth!