Is there any particular reason that you want to do this?

I don't think that doing that will free up much space, unless you store huge files in your Processing sketch.
And there is no way (that I know of) to automatically delete the temp files.

What OS do you have? (just to be sure...)
I know that in Windows, you search the control panel for "Clean up" and i believe the first result deletes unecessary files (something like "Clean up your system by deleting unecessary files")

Good luck!

I use CCleaner regularly, so I've customized it to remove Processing's crap as well.

Put a file called "Winapp2.ini" in the CCleaner main directory (for me: "C:Program FilesCCleaner").

In this file write the following (note: the forum doesn't allow backslash, so I've used forward slash in the text below)...

1. [* Processing]
2. 
   
3. LangSecRef=3024
4. 
   
5. DetectFile=%programfiles%/processing-build/processing.exe
6. 
   
7. Default=True
8. 
   
9. FileKey1=%userprofile%/Local Settings/Temp|*.*|RECURSE

... where of course you point towards the correct program file and temp directory for your situation.

This will delete all subdirectories and their contents (but not the files in the temp directory, that's another command).

You can test if it's configured correctly by pressing "Analyse" in CCleaner to get a list of files to be deleted.

I followed the CCleaner link and found this page that might answer your question (haven't dug more):
http://www.piriform.com/docs/ccleaner/advanced-usage/ccleaner-ini-files