The best way to keep your white gold white, apart from not wearing it, is to have it replated. During the replating procedure, the jeweller adds a new layer of rhodium to the existing one, returning your piece to the original shiny white colour. The price for this service depends on how worn off the rhodium layer is. It is also worth mentioning that the electroplating process is safe for your gemstones as they do not conduct electricity while the plating requires a current to pass through the metal to take effect.