The standard way we address an envelope here is "Yo, OH 44512". We almost never spell out Youngstown. Herm
I think four-lettered states should be spelled out in their entirety, when sending letters there(or FROM there). YO
The state of Maine for many years had "ME" as its postal address name. Someone finally decided that looked silly. They couldn't change it to MA because Massachusetts has that one. They use the entire 5 letters now.