If your chromed bathroom and kitchen fixtures have hard water stains that won't come off with regular cleaners try cutting a lemon in half and scrubbing the surface with the lemon halves.
Household weblog Broccoli Cupcake reported how this method removed all the hard water stains on the author's shower after the author was told by cleaning professionals that hard chemicals must be used to remove these stains. The citric acid will cut through the stains. It also works to remove rust stains from bobby pins or razor blades left in the shower.
Spring Cleaning: Natural Cleaning Tips for the Bathroom [Broccoli Cupcake]