The /tmp, /private, /var, /var/folder directories should never be manually adjusted, modified, or otherwise changed by the user in anyway. NO, you should never manually delete items in the system temporary folders This may sound confusing but it’s really not, and getting Mac OS X to clean house and ditch those potentially enormous files is really simple. What should you do? Should you delete the files yourself? Is it possible to clear them out? The answer to this is both NO and YES, NO you should never clear those temporary cache items yourself, but YES you can have Mac OS clear out the temporary files itself. You want those files removed so you can regain that disk space, obviously. How to Remove Temporary Items from Mac System Folders For example on this particular Mac which is rarely rebooted, OmniDiskSweeper has discovered some large files hanging around buried deep in one of these temporary system folders of /private/var/folders/ further buried in /g7/7p9s/T/TemporaryItems/, with those many temporary items eating up a grand total of 44GB of disk space, hardly a soft footprint:

Clean mac log files temp files