I was wondering about this too. I recently used fine sand paper on the light superficial scratches with so-so results. But the deep gouges would require aggressive sanding or grinding. On the same topic, sort of, some old frames have a massive amount of gunk built-up in the seat tube that causes even a new post to stick, which requires twisting to remove. What method, if any, do you use to clean the seat tube. I hope I'm not distracting your thread holiday76.