What is the best way to clean the rust from inside the tube before applying some protective oil?
I have evapo rust home and used it before with success, but I have to leave soaked for a while.[/QUOTE]
Coat hanger and steel wool.
Assuming you have removed BB, take a basic coat hanger and leaving the hook, cut and straighten ithe hanger out. Wrap steel wool around the hook. Insert into the tube and work it until rust is gone. Wipe out BB shell and ensure no wire and rust particles left.
Do not do this with BB still installed as pieces of steel wool will get caught up in the grease.
Spray in a protective oil such as frame saver or any good antirust spray. Should take only a few minutes. I have done this and attached an electric drill to the coat hanger which works also and of course is faster than doing by hand. Someone told me a shotgun cleaning rod with a brass brush works but I haven't tried that.