Water spots on aluminium.

[720eyes]

I detailed a BMW 335 this past weekend. On the aluminium trim there was water spots that I couldn't get out. I tried a metal polish; then different grades of paint polish (by hand). I did get them to lighten up a little, and the aluminum to look brighter, but they are still there. I don't want to mess up the trim by using the wrong product.
What would work on water spots on aluminum?

thanks

[Vegas Transplant]

Anodized.