Take potentially dangerous PDFs, office documents, or images and convert them to safe PDFs.

The Apache Tika™ toolkit detects and extracts metadata and text content from various documents - from PPT to CSV to PDF - using existing parser libraries. Tika unifies these parsers under a single interface to allow you to easily parse over a thousand different file types. Tika is useful for search engine indexing, content analysis, translation, and much more. You can find the latest release on the download page.

PDF Mod is a simple application for modifying PDF documents.

You can reorder, rotate, and remove pages, export images from a document, edit the title, subject, author, and keywords, and combine documents via drag and drop.

This gets an award for Tip of the Day :)
Unfortunately I cannot comment directly as I'm too stupid to pass the anti-spam test.