Windows Disk Cleanup offers a Temporary Files handler which seems to delete some files from C:\Users\USERNAME\AppData\Local\Temp, but not all. People around the place have indicated that it won't delete anything newer than one week, and I notice there are no old .tmp files hanging around afterwards. So I guess it deletes only files ending in .tmp, and not in subdirectories, and only when a week old. But I would like authoritative information.
Yes, by default it only cleans up files if they are older than 7 days old, but you can tweak that number to something else.
Taken from here: