Here is sample output on a file that has had hidden data removed.

C:\Documents and Settings\Docs\My Documents\file.doc scanned at 1:49:55 PM on 3/30/2004
Different revisions of document not found.
Comments not found.
Early document versions not found.
Document template other than normal not found.
VB Module descriptions failed to remove. Reason: If the "Trust Access to Visual Basic Project" security setting is disabled, the tool cannot determine if the document contains a macro. Macros might contain personal information. Review security settings and macros and delete any that contain personal information.
Smart Tags found and removed.
SendForReview RCIDs not found.
Store random number in the document check found and removed.
Embedded objects not found.
Hidden Text not found.
Same-color text not found.
Custom properties not found.
Header and footer not found.
Hyperlinks found and user prompted. Result: kept
File Paths not found.
Bookmarks not found.
DSNs not found.
Field Codes not found.
VB Modules not found.
C:\Documents and Settings\Docs\My Documents\file.doc scanning complete

Pretty handy! Here is the skinny from the Microsoft site and where to get the free tool...we recommend you add it to your digital toolbox.

With this add-in you can permanently remove hidden and collaboration data, such as change tracking and comments, from Word 2003/XP, Excel 2003/XP, and PowerPoint 2003/XP files.

When you distribute an Office document electronically, the document might contain information that you do not want to share publicly, such as information you’ve designated as "hidden" or information that allows you to collaborate on writing and editing the document with others.

The Remove Hidden Data add-in is a tool that you can use to remove personal or hidden data that might not be immediately apparent when you view the document in your Microsoft Office application.

You can run the Remove Hidden Data add-in on individual files from within your Office XP or Office 2003 application. Or, you can run Remove Hidden Data on multiple files at once from the command line. In either case, to run the tool you must have the application installed in which the document was created.

The Offrhdreadme.htm file included with the add-in includes a complete list of all of the types of data that the tool will help to remove. By default, you can locate this file in the \Program Files\Microsoft Office\Remove Hidden Data Tool\1033 directory in the drive where you installed the tool. If you installed the tool to a different directory, you can locate this file in the \1033 directory, a subdirectory of the add-in installation folder.

Notes
- You should run the Remove Hidden Data add-in on files when you are ready to publish them. This is because some of the data that the tool removes is used by Office for collaboration features, such as Track Changes, Comments, and Send for Review.

- You should always save to a new file name, rather than overwrite the original file with the new document, in order to preserve a copy of the document containing the original data.

-The Remove Hidden Data add-in does not work with Information Rights Management-protected or digitally-signed files.

Download- Remove Hidden Data Tool