mAJORD started a thread about it over at OCA if you want to check it out- he is in Brisbane.

http://forums.overclockers.com.au/showthread.php?t=902264

He has had some success.

Also Tezza over at classic computer (NZ) has been busy.

http://classic-computers.org.nz/blog/2008-12-30-de-yellowing-old-cases.htm