jetter,
I would guess that if the wire was taken off a spool, then yes, the entire spool could be processed (burned in).
Some of the more exotic designs (like AQ) that would be unpractical. I believe that having music playing through the cables to be the best way to condition them. I say this because I did own a AudioDharma cable cooker which was good, but it still required actually music time to finish the process.
At least in my humble opinion.
ozzy