Originally Posted by wolfchild

The outside of the frame is already protected by primer and paint and chemical pre-treatment which is used before painting...Rust starts on the inside and then it spreads outside. The best way to rustproof a frame is to spray some rustproofing oil on the inside of the frame. If you notice most frames and forks have very small vent holes. You can spray rustproofing oil into those vent holes and also remove the seatpost and spray some oil inside there... You don't even have to rustproof your frame, as most frames will outlast you and it takes extremely long time for a frame to completely rust out and become unusable.