Guide to Removing Sensitive Metadata from PDF Documents
But there is a difference between recognizing a potential problem and knowing how to avoid it. If you use MS Word, take a look at this guide by the NSA entitled, Redacting with Confidence: How to Safely Publish Sanitized Reports Converted From Word to PDF. It covers the different types of exposure and gives step-by-step instructions in MS Word and Adobe Acrobat for removing data.
Source: The ever useful, PDF for Lawyers