As of recent I've been seeing some PC's with internet temporary file folders (\appdata\local\microsoft\windows\temporary internet files\low\content.ie5 that contain over 1 Million files totaling sometimes as high as 60GB.
Using CCleaner is out of the question because even when there aren't that many files, deleting them by hand is usually faster. I've always found, at least for temp internet files ccleaner to be slow.
Selecting the files and pressing delete is still pretty slow, as it has to prepare them before it deletes them. You could use the Shift + Delete to delete with out recycling them first, but it still has to prepare the files. So upon looking online for a faster solution I found the following command line option.
Step 1 : Open CMD with admin privileges
Step 2: Navigate to c:\users\(username)appdata\local\microsoft\windows\temporary internet files\low\
Step 3: Type del /f/s/q content.ie5 > nul
Step 4: Press enter
While this still will take some time to complete, it's a lot faster than holding down shift and pressing delete and no comparisonly faster than using CCleaner. (I would not be surprised if it were to take CCleaner 24+ Hours to delete)
Once finished the folders will still be inside content.ie5. So just open the directory and delete the empty folders or run ccleaner to do it for you.
If you can do this from inside a bartpe environment the entire processes is even faster still.
Hope this helps