Hi there. You shouldn't have to polish up the veneers. Correctly manufactured veneers are glazed in a furnace at high heat. This means that a layer of glass seals the surface of the ceramic. However, if the veneers are "under-glazed" they may have a dull look and are "non-reflective". Light shining on them is absorbed and not reflected. Veneers can be polished up to give the appearance of a glazed look. This is done by using a silicon rubber wheel to smoothe the surface and then using pumice on a rotating brush. Finally different grains of diamond paste can be used to create the desired effect. Reflected light should scatter in manny different direction. If this is not done correctly, you may end up with a smoothe surface that mimmics an extremely worn, older looking tooth. Please call us if you are in our area and we may be able to help you. Kind regards Michael T.