While doing a car restoration some years ago I learned something about scratched metal that should have been obvious to me but wasn't. You can't smooth out scratched or gouged metal by sanding and polishing unless you remove a large amount of metal in the vacinity of the scratch. If you polish a gouge, you end up with a polished gouge. The best solution is to fill the gouge to a level slightly higher than the surrounding metal, and then sand it down to the same height before polishing. On metal that means filling the missing metal with welding or something similar. ... If, instead, you remove enough metal to blend the gouge so it is not as obvious, you may remove enough metal to weaken that entire area of the log.
