Removing top coat of paint

Recently picked up a 1930's JD. It has been repainted with something that looks like it might be enamel. The paint is sunfaded, and does not look so good. Some has even worn off to where the original paint is showing through. Am thinking about trying to remove only the top coat of paint to reveal whatever else is left of the original paint. It does not matter if all the original paint is still there, I would like to just get the newer paint off of it, and leave as much of the original paint as possible. Chemicals are probably the way to go. MEK would likely take too much off too quickly. Some other choices might be Srip-Eeze, oven cleaner, mineral spirits, or xylene. Has anyone ever tried this before? The desired end result is to have a tractor in its original farm clothes. I will protect any unpainted metal with a 50/50 mixture of tongue oil and turpentine (Thanks for the tip Regan!) when finished. Thank you. Greg