I know this debate is as classic as Ford vs. Chevy but I've been twisting wrenches and busting knuckles for over 40 years and this is the best I've ever tried.
I know this has been discussed here over the years and everybody has their favorite but I'm just sharing for what's it's worth. I don't have any stake in the company...lol.
If your trying to free up a frozen Veeder Root this stuff is a miracle, however on the down side it stinks really bad. You can find Free All at O'Reilly Auto Parts or order from Amazon