%systemdrive %\windows\temp правила удаления
Это - больше безопасности, связанный, но Опасный Бизнес очень хорош.
The rules are there isn't one.
Some well-behaved apps will delete their temp files once they're done with them, some will not. But by default, Windows does nothing to the system or user temp directories, and will allow them to grow indefinitely (until the disk runs out of space).
If you want to periodically purge this directory, the cleanest, easiest way would be to use a script that's attached to a scheduled task, or startup/logon or logoff/shutdown script to delete files older than... whatever you decide is best for your environment.
Honestly, though, in the vast majority of cases, this is a wasted effort... if temp files are filling up your system drive, something else is going wrong, and you should correct that, if at all possible.