Following the many questions we get about this topic, we decided to upload a video that shows how to remove the cog from your Jobo lid.
The cog (#1505) was designed to be a permanent addition to the lid, but as seen in this video, can easily be removed, and replaced (if damaged), or for converting the lid for use as in inversion lid (red membrane cap #03046 will be needed).

Check it out on youtube:
http://youtu.be/JGWEGjoWNmQ