Searching for Returns??

[FishSniffer]

I need to have my database of subscribers in a particular format so when I send my mailing list to the publisher it fits into the USPS requirements. I guess recently my publisher notified me that I have several returns in my database that are pushing info onto the next line and thus out of the proper format. I was wondering how on earth do I search for these returns in my database so that I can fix them??