I'm trying to get the windshield washer fluid and coolant reservoirs for my Malibu cleaned up. The washer fluid reservoir has that blueish stain on the inside, from years of the blue washer fluid, and the coolant reservoir has that sort of dirty brown stain in the lower corner. Anyone have any tips or tricks for cleaning these things up? Any kind of special cleaner? Bleach? Looking for some ideas here. Thanks in advance.