What he said. If rust is gone to the eye just use a rust inhibiting primer. If rust is still present probably use a converter. Many available and they can be painted over (they act as a primer). Framesaver, Boeshield, etc a=go on bare metal, usually inside the tubes. They cannot be painted over. They leave a thick, waxy residue to protect the metal. You can use oxalic acid (deck bleach) or phosphoric acid (Naval Jelly) to remove rust also.