Rules for cleanliness when working on transmission

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2009 Audi A4, 2008 Audi A4, 2007 Audi A4, 2006 Audi A4, and 2005 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Carefully clean all joints and adjacent areas before disconnecting.
Place removed parts on a clean surface and cover them. Use sheeting or paper. Do not use fluffy cloths!
Carefully cover or plug unpacked components if repairs cannot be performed immediately.
Only install clean parts: Remove packing from replacement parts immediately prior to installation and not before.