this kind of stains comes on outer surface of tooth enamel and can be cleared by scaling and polishing of teeth .if the stains are intrinsic in that case you may require bleaching
followed by veneering of tooth
avoid breathing from mouth .
first of all take care of your oral hygiene .
follow brushing your teeth twice a day.
Visit dental surgeon
for scaling and polishing of teeth.
Use colgate-total tooth paste.
Rinse with listerine mouthwash. Before going to sleep.neer formation