Banana peels are able to whiten teeth and remove stains. A ripened banana should be used, perhaps, with a hint of green at the ends. At this stage, the peel has the highest level of potassium, which is responsible for the brightening process.
To whiten the teeth, after the banana is peeled, cut off a section of the peel with kitchen scissors. Rub the skin over all the teeth for two minutes, coating the teeth with the substance inside the peel. Next, brush the teeth with ordinary toothpaste and rinse with water. While the whitening process is underway, calcium and vitamin D from the peel also help strengthen teeth.