Repeat until your headlights lose some of their yellow hue. Rinse your headlights thoroughly and dry. To further protect the lenses, apply a coat of car wax. Use a clean, soft rag to rub the wax on in a circular motion, and buff out after a few minutes.
Sodium bicarbonate (IUPAC name: sodium hydrogen carbonate) is a chemical compound with the formula NaHCO3. It is a salt composed of sodium ions and bicarbonate ions. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). The natural mineral form is nahcolite. It is a component of the mineral natron and is found dissolved in many mineral springs.
An antacid is a substance. An antacid is a substance that will counteract or neutralise an acid. So an alkali such as NaOH is an antacid, but not suitable to take to relieve excess stomach acid. A weaker base is better such as Mg(OH)2 as in milk of magnesia, or Al(OH)3 or CaCO3 can neutralise an acid. http://en.wikipedia.org/wiki/Antacid has stacks of relevant information. 'Chemistry is not just the study of matter; Chemistry is the study which matters!' - Kingchemist.