Olive oil and apple vinegar treatment. Prepare a mixture from a teaspoon of olive oil and one of vinegar. Dip the toothbrush in this mixture and brush your teeth, and then rinse thoroughly with water. Apple cider vinegar is rich in calcium, potassium, nutrients good for your teeth. Also, malic acid is used as an ingredient in toothpaste because it removes stains. You will notice that your teeth will get whiter in time! Warning: do not abuse this treatment because apple vinegar can weaken tooth enamel. Use it no more than twice a week.