Care and Maintenance of a Saxophone
Occasional maintenance

Key oil should be applied in small amounts to both ends of the axle that supports the key. Put a little oil between the key post and the key axle, and then remove any excess oil.
This prevents the key from running out of oil, and it does not need to be done frequently. If the oil does run out and the key starts to squeak, apply some oil; otherwise, once every two to three months is sufficient.

Rust is not a welcome sight, and in some cases, it has a rank odor.
Metal polish and brass soap work well to remove rust and clean the inside of the bell. However, there is a key on the bell, so be very careful not to get any polish or soap on the pad. Any music store should carry all of these items, so please visit your local music store if you need them.
As long as it is not too bad, rust will not affect the performance of the instrument.