How do you address letter to former mayor?

As a former Mayor of a relatively small city in the U.S., it has always been said to me that "once a Mayor always a Mayor", it seems easier for non- elected officials- regular citizens to want to remove an honor bestowed upon someone in our political system.

I would suggest in introductions "the former Mayor, John Smith, in person greetings to be "Hello, Mayor Smith, " they will then say to refer to them less formally or it will be clear you made the right choice. In written communications, The Honorable Steve Jones is appropriate. Recognizing a person's service to their country by participating in our form of government does not eliminate their citizenship, but does acknowledge their service and oath.

* Since the person is no longer mayor and they are replaced then it would revert back to 'Mr' or 'Ms.'