Well here is a way to make an unreleased song. Let's take the Anakin/Obi-Wan fight scene. When Anakin chokes Obi-Wan on Mustafar we hear drums. These drums are, sadly, not included on the soundtrack. So what you do is take the scene into audacity and separate the audio channels. Listen to each channel 1 at a time and delete the parts of each channel that are sound effects (and/or dialogue). Then you take the soundtrack song and move it into position to line up with the movie music. Delete any thing other than the drums and what do you get? A film version of "6M4 Heroes Collide" aka "Anakin VS Obi-Wan".