Just a reminder that the OP doesn't need to build a "correct" address formatter that follows CASS certification rules. He needed something that would standardize typical spellings of address parts just to do a simple dupe check before he send data to his authorized CASS Certified SAS. He has to send it to someone that carries such a certification to get breaks on postage.

So, no need to get real fancy here. Replace the parts, single up spaces, drop special characters, and do a dupe check.