You likely already have the ingredients for the most effective penetrating oil available -- 50/50 ATF and acetone. It's widely known that it works as well as or better than the more costly commercially-available products; we certainly do and that's why we don't sell them. The problem with making your own penetrating oil is storage and application because the acetone evaporates and eats your bottle alive.
We sourced this glass bottle specifically for this duty. Mix up 4 ounces of your homebrew, use as needed with the included glass dropper, and give your concoction a sexy, cobalt blue home.