Be careful doing this, if you plan on using any of those tunes again. You'll end up having to add them to another collection & rescan them again. I made this mistake. I suggest just moving the collection/s to a different folder (if you plan on using them again). This can save hours (in my case days) of rescanning.
wound up having about 8 different collections ,,tried right clicking to delete non used/empty ones ,, how would you achive this 
