I discovered Super Slick Stuff more than 30 years ago. There were some very rusty bolts I needed to remove on a boat that stayed in salt water 24/7. I tried WD-40, then PB Blaster, then 3-in-1, and liquid wrench – no luck moving those bolts.
Ace Hardware had Super Slick Stuff at about twice the price of the others. I tried it, and within a couple minutes all rusted bolts came right out. Thinking Super Slick Stuff maybe had an advantage with the others working on the bolts over a period of weeks, I tried it on the other engine and sure enough, this stuff works.
It has been my only penetrating spray ever since. It does not absorb water and has a fresh orange smell. I have never used it on my firearms as I have always felt it is too light of a lubricant, but never say never.
I have mentioned it several times before: