Over the past 40 years I have never seen a frame rust out from the inside. All of my commuter bikes have been steel. Here in the north Midwest tons and tons of salt is dumped on the roads every winter. Never has any of my frames rusted out. Never. I think it was pure marketing genius by JP Weigle Frame Saver to create a demand where non existed before. Squirt some oil down the tubes and forget you ever did it. Now, go ride that bike!!!