Calcium stains in dishes

A friend gave me some older dishes from a BP set-up he used to have. Two of them have white stains on the sides that I imagine are from calcium build-up over time. If I run these through the dishwasher, can they still be harmful to my BP? Or is there a safe and effective way to remove them?

Vinegar is excellent on hard water stains, and non-toxic. It is acidic, so it can damage some surfaces. Depending on what the water dishes are made out of, vinegar will probably work very well.