Ha! I *just* read this in another thread:
I posted here to this forum when I had an aluminum Rino Cambio seat post solidly seized into a steel Bennotto frame.
On this forum the lubricants of choice are Liquid Wrench, Kano Kroil and ATF mixed with acetone.
Machinist's Workshop magazine actually tested penetrants for break
out torque on rusted nuts. Significant results! 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 Automatic Transmission fluid (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. A local machinist group mixed up a batch and 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.
Sorry I can't credit the OP