Our forum-friend 'Morgan Kane' (Steinar) did an extensive gun oil test on this very forum last year. You may want to look for that thread.
Update:
Hah, found it!
http://forum.lugerforum.com/showthre...light=oil+test
WD 40, Mobil 1 engine oil, Break Free and RIG + P Stainless Steel won the 'salt dip test'.