I had very rough wheel arch protectors. Used 1000 grit sand paper (don't forget to use water) and sanded them down. Far better now. I then used Back to Black applied with a paintbrush. Need to do a couple coats. Doesn't last long, haven't given much thought what to use instead. As for the fist bull bar; mines in great knick, but applied Back to Black and seemed to bring up the colour. Hope that helps