Baking soda is a great natural method to help dissolve calcium buildup. It is highly effective in removing hard water stains from dishes in the dishwasher. To use baking soda, first, sprinkle some of it onto the bottom of an empty dishwasher and run a normal cycle with hot water. This will help loosen the calcium build-up and remove it from the surfaces. You may need to repeat the process a few times for more stubborn deposits until the buildup is completely gone.