If your nails aren't looking nice and healthy, either are your fingers or your hands. You can't have one without the other, and yellow nails is a horrible sign of unhealthy hands, especially if you're a smoker. But you can get rid of that yellow tint. Scrub your yellowed nails with whitening toothpaste. The same principles apply to your nails as your teeth, so toothpaste is the perfect solution… Nailed it!