Question : search/scan Exchange for "credit card numbers"

As part of a security audit, we need to scan a MS Exchange server for credit cards.  What is the best way to do that?  Tools?  Scripts?  Powershell?  How about scanning the backups vs unmounting the EDB?  I have not admin'd an Exchange server in years so I don't know all the ramifications.

Thanks for your help.

Answer : search/scan Exchange for "credit card numbers"

You can also use Mapi mailbox scanners, which will allow you to scan individual mailbox with certain key words...