Thanks for the explanation, burdar.
As the car is usually only driven when the sun is out, it is worth to think about it. Many years ago I've bought an aluminum bicycle that was painted pink. I didn't like the paint and wanted polished aluminum, so I scratched the paint off and polished the bike until it looked like a mirror. I finished with wax. The bike is still shiny, but needs more cleaning. Some guys even drive polish aluminium wheels. And yes, its a lot of work to keep it shiny. RPM is worth a try then.
I don't know what exactly is anodising but I think if I use fine sand paper I will get it off too.
Thanks for making it clear for me, I will think about and not just start.
CU
walkAbout