The best release agent I've ever used I discovered last year which is a 50/50 mix of Acetone with ATF or Brake fluid.Works better than any shop bought one,
PB Blaster=ok. A 50/50 mix of acetone & ATF=Best Ever! Here's the cold, hard facts from the April/May 2007 edition of Machinist's Workshop. They did a test of penetrating oils where they measured the force required to loosen rusty test devices. Buy the issue if you want to see how they did the test. The results reported were interesting. The lower the number of pounds the better.
Penetrating oil . Average load .. Price per fluid ounce
None ................. 516 pounds .
WD-40 .............. 238 pounds .. $0.25
PB Blaster ......... 214 pounds .. $0.35
Liquid Wrench ... 127 pounds .. $0.21
Kano Kroil ........ 106 pounds .. $0.75
ATF-Acetone mix.. 53 pounds .. $0.10
From another thread