Nail Whitening Trick: fill a bowl with water, add a Polident tablet to the bowl and soak the fingertips for 5 minutes. If your nails have yellowed from a particular nail polish, it may take up to 3 times to remove the stains.
My nails were looking yellow and dingy, so I tried this whitening technique using baking soda and peroxide and it totally worked. 1 tbsp peroxide, and 2 tbsp of baking soda! Let the paste sit on your nails for 5 min, and viola, its wonderful!