hmm.. I've thought about it though.. let us say you
wanted to download it for viewing from the web. since it
is downloaded into the temp folder when it is opened,
will running the macro before close remove it?

I would strongly urge you not to even think about trying
to clean up temp internet files on other peoples systems,
with this DOS method or any other. Some would classify
that as a virus, even if only trying to selectively delete
your own your file that someone has downloaded.

Also it appears that your bat file removes the directory
tree of thetemporary internet files, does that affect the
functioning of IE at all?

Reading what others far more knowledge than I say on the
subject (the search I originally suggested) the IE folders
are recreated if not found. That indeed seems to be the
case, but I've only tested with IE NOT running.
Personally I would not want to run the bat file
automatically when closing a wb, at the very least get
Msgbox confirmation. But you did ask!

FWIW, several suggest putting the deltree commands in
AutoExec.Bat to do a clean up on start-up.
Other suggested delete commands:

deltree /Y c:\windows\cookies
deltree /Y c:\windows\temp\

Note the extra "\" with the system temp folder only
deletes contents, not the folder itself.

Regards,
Peter