Are there any clean-up tools for Address Book data?
Before you do anything, you can back up your Address Book database as an archive so you can restore it later if you make any edits that you don't like.

In Address Book, choose File: Export...: Address Book Archive... and save the archive. 

Are you running Thunderbird 9 on Mac OS X? You can configure Thunderbird to read and write to the Mac OS X Address Book instead of using the Thunderbird address book. In other words when you open the Thunderbird Address Book and create or modify address book entries, it manipulates the Mac OS X Address Book's database.



In this way, could you use Thunderplunger in Thunderbird to clean up your Mac OS X Address Book?

I don't have an exact solution but I would like to tell you about one simple tool that might prove helpful.

AB2CSV

enables you to export all or part of your Mac OS X Address Book as a CSV (comma-separated value) file. You can import that into any spreadsheet or database program for further editing.

You can also use AB2CSV to export all or part of the Address Book database to one large VCF file.

Next, Apple Address Book can import a .CSV file or a VCF file that you have edited. In Address Book Help, there's a page for "Import contacts" that explains how to do it.