It is pretty amazing what 30 years does to a vehicle's interior. When we pulled that nasty blue carpet off the interior floor we were surprised at the amount of rust we found. This was one of the rare instances where we actually worked on both halves of the car. It didnêt make sense to only treat half of the rust because anything untreated would have continued to spread and ultimately ruin our project. After we sanded all the surface rust to help identify the really affected areas, we went right for Dupli-Color® Rust Fix which basically stops rust on contact. We treated the entire floor just to be safe and then it was on to the door panels.