Am in the process of painting my small bumpers. Thought about having them sandblasted, but didn't want to spend the money on bumpers that had some minor dents in them. Some 80 grit paper on a drill worked great. I then finished it with some fine stuff. Primered and painted semi-gloss, looks pretty decent. Will post pics when dried (tomorrow?)
This was also a transformation from the big '75 bumper to the little one. Didn't cut the fenders; cut the valance instead.