Nothing feels better than freshly painted nails. But it can be frustrating when removing them. No matter how much nail polish remover you use or how much you scrub, you may be left with yellowed nails. Thankfully, whitening yellow nails is a very simple process and can be done with items you already have at home.

But getting your nails clean is only half the battle. It is equally important to make sure it never happens again. We asked Dr. Dana Stern, a board-certified dermatologist specializing in nail health, for the full story.

The first step to whitening your nails is to know why they are yellow in the first place. Says Dr. Stern, "If you're constantly battling nail stains, you want to be properly diagnosed and treated."

Often it will be attributed to your nail polish, but color changes may indicate an underlying health problem, such as poor liver or lung function. Additionally, if your nails are thickened and hypercurved, you should seek medical attention. It could be a sign of yellow nail disease, an uncommon but serious condition.

The good news: removing yellowing is easy. If the stain is fairly light, try scrubbing it off with whitening toothpaste and a damp nail brush for a few minutes. If that doesn't remove it, or if the stain is severe, "dilute the hydrogen peroxide to thin it out," Stern says.

To make the stain-removing concoction, simply mix three to four tablespoons of hydrogen peroxide and half a cup of warm water in a bowl. After soaking for two minutes, gently scrub and buff the nail surface with a soft, clean toothbrush. Then rinse your hands, apply the lotion, and you're done.

For maximum results, Stern recommends repeating this process two to three times a week.

While yellowing is common and unavoidable with regular nail polish use, there are several steps that can reduce the likelihood of yellowing nails. Stern recommends getting into the habit of using a base coat every time you apply nail polish. This way, a smudge-proof barrier is created between the nails and the polish.

It is also important to pay attention to the dyes in nail polish. Any shade, brand, or formula can stain the nails, but darker shades such as purple, blue, dark red, and black are more common side effects.