Calcium Build-up if you have "Hard Water"

To remove the calcium build-up which is often accompanied with "hard" water, boil undiluted (white) vinegar and let the calcium coated item "sit" in it for a few minutes. I have boiled vinegar in a coffee cup before and held the cup to my water faucet for a few minutes, and the calcim breaks up and washes away. My Grandmother runs her vinegar through the coffee maker (which cleans it very well), then she pours the hot vinegar in the toilet to keep the calcium from building up on the bowl surface.