What can I do with the Joker if I remove every tile from its meld? (Can I even do that?)
Wow, they've really been messing with the rules of the game.
In every version of Rummikub that I've ever played (and I'm one for reading the rules before we start playing), this kind of thing is explicitly disallowed like this:  


  A combination which contains a joker can have further tiles added to it, but nothing can be taken from it, nor can it be rearranged in
  any way while there is a joker in it.


Here's a link if you're interested:  http://www.pagat.com/rummy/rummikub.html

Obviously there are different publications of the game with different rule sets, but I far prefer this "joker melds cannot be split!" version.