FYI....picked up from MTF:
Some of you might appreciate this. Machinist's Workshop magazine tested penetrants for break out torque on rusted nuts. Results are below, as forwarded by an ex-student and professional machinist, Bud Baker. They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.
*Penetrating oil ..... Average load*
None ...................... 516 pounds
WD-40 ................... 238 pounds
PB Blaster ............... 214 pounds
Liquid Wrench ......... 127 pounds
Kano Kroil .............. 106 pounds
ATF-Acetone mix.......53 pounds
The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Our local machinist group mixed up a batch and we all now use it with equally good results.
Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price.
Source:
http://forums.thecarlounge.net/showthread.php?4547049