I discovered this by accident one day... but I was surprised at how amazingly well it works:
In order for this to work, you'll need Listerine WHITENING Pre-Brush Rinse (the white bottle). There's something about this particular kind of listerine that makes this work. Other kinds won't work for this.
Put a small amount (teaspoon or two) in your mouth, and then bring in your lips (like an old lady without densures). Let the listerine work on your lips for a minute. Spit it out while rubbing your lips together. Then take a cloth or tissue and while smiling, whipe the lips. Then repeat the listerine treatment once more. Afterwords, apply lip balm. It's amazing.
It does not turn the lips white. Listerine Whitening may foam. It works, but do at own risk. It's been a great help for me.