when I work on my 58, I scrape junk off of where I am working, like when I replaced all the brake lines, I had a lot to scrape and clean. Same with re-wiring tail lights and cleaning up wiring underneath. I think it also depends on where you live, and if it is driven all winter on wet and salted roads! I would not be too concerned with cleaning if you are going to re-coat it as you go but ,hard to beat 60 years of grime for protection for a working truck! (not really what you want for a show piece though!)
