Brown spots and stains are usually a result of cigarettes, coffee, cola or wine consumption. Over time, these beverages stain the teeth on the surface and these stains can enter cracks and crevices present on the enamel of the tooth. Similarly, yellow teeth with age teeth become yellow due to exposure to such substances as well as the dentine layer becoming harder and dense. Rinsing or brushing your teeth after eating and drinking may help eliminate surface stains but will not treat deeper staining. Consult your dentist about a suitable teeth whitening system to assist brighten your smile.