If clicking the lightning icon in the Media window doesn't remove some media, then the media
is being used somewhere in your project. All media in the Project Media list, used or not,
will be copied when you "Save As" with the "Copy Media" option selected.
You can right-click on the media name in the Project Media window, then click on "Select Timeline Events". The selected media is then highlighted on the timeline.
Steve Mann
MannMade Digital Video
http://www.mmdv.com