google POR15 and Rust Bullet and Eastwood
Fordtech,
POR15 and Rust Bullet and Eastwood make products hawked for cars, trucks and heavy equipment to use on rusty steel. I think the way POR15 and rust bullet works is it sticks so well the corrosion tends to stop. These three companies are mentioned on many threads about old cars and rust.
With the rust bullet I got, I got kit(s) for 20 bucks each that have two dinky 4oz tin cans, two brushes, gloves.
It is not a product what you open, 1/2 use then use a year later.
About any stray product that gets dropped on one's clothes, glasses, hands and has to be worn off. About nothing will remove it. Thus if the object to be covered is cleaned off the stuff sticks real well.
A friend that fixes up old cars uses POR15 and says it is better than Rust Bullet, I am not sure. Both products are all over the web and Ebay too.
I have used rust bullet on my 1985 Toro mower too.
The failure mode with any repair is there is still corrosion going on under the fancy paint job, this is quite common. Rust can be a cancer and one does not remove it all , and many coatings actually trap moisture and feed the old corrosion one missed. I think the theory with POR15 and rust bullet is the barrier is better, thus any tale tail rust is not helped.