It seems that 40 years ago they used to use real steel, not recycled soda cans. All traces of surface rust have disappeared. I used an angle grinder with a flexipad and fine grits for the tubes. The lugs were sanded manually.
In retrospect, it would have been much easier (and tons quicker) if I had it sandblasted. Though, I did not know anyone who has experience in sandblasting bike frames and doing it safely with fine mixes.
