I live deep in the Rust Belt, and these are the products that I find actually work. First, wash vehicle with "Salt-Away", it chemically neutralizes salt . It has a high dilution rate, so a little goes a long way . Originally developed for the marine and aviation sector. I then have "Rust Cop" applied , a yearly process. It is a "Carwell " product with a long track record and excellent warranty. You can Google these products. I also install marine zincs, one each on body, frame.They will take the corrosion "hit" first, hence the name "sacrificial" or "noble" metal. Best to do from new, but Salt Away in particular will slow the corrosion process. Good Luck !