Even when my radiator is washed and de-bugged, parts of it are "brighter" than others - part looks gray and dingy, part looks more clean and silver. Any experiences with anything that will give the radiator core that new, clean aluminum look?

 

Mine is shiny where the tin solder is, could it have been the acid flux (different than reflux) used before soldering?. I wonder if wheel cleaner meant for aluminum would brighten things up.

 

sprits vinegar for a few mintues and rinse with water?