So I have this rust on the inside if my door that seems to be a result of the door rubbing against the frame. I want advice from you guys on what to do. I'm thinking if knocking the heavy rust off of the inside and then hitting it with a Truck bed liner or undercoat, and then the outside sanding the surface rust off (I think that's all that it is) and priming it and then painting it with the perfect match paint. I'm just not sure if I should just paint that spot, a square section, the bottom section of the door with tape along the seem I guess you could call it or just paint the whole door? Help me guy!?!!??!??