Eliminate MRU (My Recent Documents) completely

Hi Folks,
I have a customet that has multiple users that create large files (CAD -
SolidWorks etc) and they are having performance problems. I have narrowed it
down to the most recenty used documents (drawings) somewhere in the cache. I
have done the following to no avail. Unchecked the save my recently used
documents, done the registry change that removes the MRU, Installed TewakUI
and set it to clear on exit. Unfortunatley that is not going to work for
them. they need to exit & log off to clear it......or go into toolbar
properties, start menu, customize, advanced, clear list. All users are not
savvy (or patient) enough to do so.
I need to know if anyone does, how can I disable this from running in the
background. Even if told to not save this list there is something saving it
somewhere. With all the changes above, if I go to "Clear List" it takes 10-20
seconds to complete and then machine speed increases quite a bit opening the
next file. Is there a location to a file that the "Clear List" button points
to that i can call in a batch file or script or something to make it simple
for users? Thanks in advance. Posting this in a couple of areas to try to
find answer. Not sure which one it applies directly to . Thanks again. Joe K.