Before you can restore you must first remove. With old cars this is often easier said than done as rusted fasteners weld themselves together with a shear strength that goes well beyond using just brute force for removal. Over the years I have used all kinds of penetrating oils, applications of heat, and general prayer to help get fasteners to come loose. Despite all of this experience I never used a product that has been around for over 50 years! PB Blaster. I had heard about it but never gave it a second thought until one day I saw it in the store and picked up a can. Upon using it first on the Dino I could not believe how well it worked to loosen rusty nuts and bolts. Now every fastener gets a shot of PB before removal and extra tough ones get a pre-treating of 10 minutes or so.
At under $10 this is one of the cheapest and most valuable tools you will ever use.