Doc Scrubber lets you see that information, and scrub it from files before sending them to others. It is a freeware document analyzing application.
Here are some screenshots to illustrate the features and user interface of this application:
Analyze and scrub hidden and potentially embarassing data in Word documents. Screenshot of Doc Scrubber - 512px · 419pxDelete sensitive data from your .DOC files. Screenshot of Doc Scrubber - 480px · 376px