Removing corrosion from a saxophone can be a simple process if the type of corrosion is properly identified. Corrosion can come in the form of rust, metal degradation or oxidation. Identification is the key to proper removal.
Look at the corrosion in bright light. Brown raised spots indicate rust. Moisten the sandpaper with water and lightly rub the spots. Slowly increase speed and pressure until the spots are gone.
Oxidation is black or green in color. To remove from lacquer saxophones, dip the cotton swabs in the water-alcohol solution and wipe it on the corrosive areas, then use the soft cloth to wipe clean. Buff with the lacquer polishing cloth.
Remove oxidation from a silver horn using metal polish. Apply a thin coat with a soft cloth. Wait for it to dry and remove and buff with a cloth.
Corrosive metal degradation is identified by lacquer breakdown and discoloring of the metal. Clean the area of dirt and buff with steel wool in a circular motion. Use the metal polish (for silver) or the lacquer cloth (for lacquer) after using the steel wool. You may have to repeat this process to completely remove the corrosion.
Some metal discoloration due to corrosion may be permanent.
Steel wool, sandpaper and polish can all remove metal from the horn. Although this is necessary for removal of corrosion, be careful.