This isn't original, but I found that a 50/50 mix of ATF and acetone works
better than any commercial product. Squirt it on several times a day.
Rap with a hammer, add some more, come back and presto, it's loose.
try a 50/50 mix of ATF and MEK (methylethylketone) soak it in a shallow steel baking pan or steel container or keep it mixed in a steel oil can set up. May want to stir occaisionally, likes to seperate, like oil and water. no rubber or plastic dispensers the MEK eats those like kids eat pizza