Found this, from Machinists Workshop magazine.

February 2, 2008
Machinist's Workshop V20 number 2, April/May 2007, page 35
Article: “Testing Penetrating oils”

This reports a test of penetrating oils where they measured
the force required to loosen rusty test devices.
The details reported here were validated by the original
article author.

The table below extracts the results table The lower the
number of pounds the better. Interesting that a simple mix
of acetone and power steering fluid (PSF) works the best!

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
PSF-Acetone mix. ..53 pounds $0.10 (50/50 mix)

Note from original article author:
These are loads required to free the test piece after
8 hours of immersion in penetrating oil. This is
probably not representative of a quick squirt just
before a wrench is applied.

© Copyright 8 February 2008, 63Avanti@sterkel.org
Permission to print and post on the internet in this form received from the author 8 February 2008.