I had some of the same thoughts and questions. I'm not certain, but the sections of the video at around 0:40 and 1:00 lead me to believe that they may have initially used some type of chemical stripper.
If you haven't done so already, check out the comments for the video at
http://www.youtube.com/all_comments?v=eu3OExKfFR8 - they provide some addt'l info from the person who made the video and others.
--E