I know this is for a limited audience but curious what kind of succes people have had with getting rid of curb rash. On a couple of occasions where it wasn't deep I was able to file it down and then follow through with sanding and buffing with very good results. Problem is I have a few quite nice caps but their weak point is the curb rash. I have a talented young welder doing a staniless steel handrail on my project so am going to see if he can do some welding on the perimeter to build it up and then am hoping to be able to finish them off again. Anybody made any attempts at this or had any success?
Have done basically what you've done. Put some 320 on a rotary orbital sander and sanded out the rash. Never did go thru but don't know how close I might have come. They buffed up real well after.