Hello. I've polished the valve cover and other parts of my bike. I ended sanding with 2000 sandpaper with water, in a paralell motion, and after that, I polished the parts with polish liquid in a circular motion with a cotton rag. The result was almost perfect. You could not see any trace of the sanding process. After that, I applied Zoop seal. I don't know if it is just suggestion, but it seems that the surface of the bare aluminum has changed. It looks as if it had a thin clearcoat over it. I don't know if it will resist the corrosion. I will know it by next summer, given that I live in a very wet area.
