A bit of clear nail polish dabbed over places where paint has chipped away from metal surfaces, such as on this lady's bicycle, will serve to protect the underlying metal against corrosion. My brother taught me that.
It was the Navy that taught me that paint has a purpose beyond providing us a convenient method to color objects to our liking. Surface preservation, folks.
Pentax K20D
S-M-C Takumar 105/2.8