I bumped into this on the internet and it seems to work for most videos.
Just put “&fmt=18″ at the end of the the Youtube address and most videos will be cleaned up. There are some it won’t work on but here is an example.
http://youtube.com/watch?v=Doh6uIZEX_I
http://youtube.com/watch?v=Doh6uIZEX_I&fmt=18
And this is the guy who came up with it. [...]
