Advices for teeth whitening. Have your pearly whites lost their luster because of dingy gray or yellow stains? Stained teeth can occur as we age, but some common foods, drinks, and even mouthwashes can stain teeth. Do-it-yourself remedies can help whiten teeth, and avoiding substances that stain teeth can stop further discoloration. Use these secrets to whiter teeth to restore your bright smile. Chew Gum That Contains Xylitol: Multiple studies have shown that chewing gum that contains xylitol twice daily helps fight tooth decay by lowering plaque buildup. Brands like Trident make gums with this ingredient, so pick up a …