Absolutely do not sand or emery board those terminals. Pat is right. Clean with Electro-sol or even WD-40. Make sure to disconnect the battery before you do this and let dry. Take -dielectric grease(blub grease) and work it into the terminals. Replace fuses. Those terminals are coated with thin layer of conductive alloy. If you take sand paper or emery boards you'll take that coating right off those terminals and leave grit. You'll have more problems down the road with moisture and even more corrosion.
