I have been using a product called "Rust Converter" made by Klean Strip.
I have been very impressed with how this works and wanted to share. It is one of the "turns rust to a black primer" products but I believe that this one is special because it is completely clear and colorless. It is basically a clear colorless paint which will neutralize rust.
I like the way that this product works because if you have an area in the engine compartment or trunk or interior that has some surface rust you would like to address, but also has original paint, when you use this product the rust is neutralized, coated and turns black, and the original paint quality is actually enhanced in the form of a clear coat.
The black "rust" area is presentable and the original paint is much better that it was. This goes back to the question of what is original. I would expect a 40 -50 year old car to have some minor rust/discoloration in the engine bay and possibly other interior areas. This type of product allows you to neutralize such rust, but also keep the original paint in a very presentable way and protect it for the future as well.
There are probably other products like this, but this is the only one that I have seen. I have been purchasing it from Wal Mart in a 10.5 oz spray can for about $4.50. It is solvent based and since there are no pigments, you do not need to shake (no ball) which is a little strange. Disclosure I have no financial interest in Klean Strip :)
Fred Joslin
Back to the Home of the Forward Look Network