Over the past years, I have removed plenty of songs from my iTunes library, but not deleted the files, and now my Music/iTunes folder is double the size of what iTunes reports as my library size. I don't care about any of the songs I have removed from my library. Is there any way to delete all of them? Thanks in advance!
There's a handy AppleScript that will identify files in your iTunes folder that aren't in the iTunes library: Music Folder Files Not Added.
Download the file, open the .dmg and add the script file to
~/Library/iTunes/Scripts (you may need to create that folder if it's not there already). Then it should appear under the script menu in iTunes (a scroll icon between the Window and Help menus).