Tests have been done hundreds of times……results are always the same. Best store bought is Kroil and at onetime was only in the industrial sector. Acetone and ATF always wins….now the big question which ATF.. at one time it was A or F….both long gone.
I grew up on MMO and Liquid Wrench. I never combined them.. hmmm. I was able to un-stick marine engines with decent success with MMO and some patience. I guess a solvent like Liquid Wrench or acetone (even diesel) would let it creep in more betterer.