if you ask about removing the ACW files after you are done playing the ACW, it is quite simple... when exiting the launcher choose
RESTORE VANILLA. by doing that, all of the ACW files will be removed to the ACW folder.
if you are talking about TAR, then you use their launcher to do the same. also, before playing the ACW you choose
SETTINGS -> CHECK FILES and remove all of the files that are neither vanilla nor ACW. those files will be moved to the
NONVANILLA folder which is easy to access from
FILE -> GO -> DATA FOLDER. when you want to play TAR again simply move the TAR files from nonvanilla folder to your data folder.