2007 Chevy Silverado LTZ Window Trim Corrosion

I have a 2007 Silverado LTZ with streaks from corrosion running down the rear doors.  It is coming from beneath the window sill trim.  The corrosion is from aluminum and not steel.  The dealer said that it could be cleaned with Mother's or MaGuire's cleaner wax.  My question is this, has anyone else had this problem?  Did you or your dealer find a permanant solution?  I've owned Chevy trucks all my life and never had this occur before. I would appreciate any feedback that's out there.