Are you sure the extractor claw isn't grabbing the breech face?
Honestly...50/50 or 30/70 cut automotive automatic transmission fluid (the cheap stuff) and diesel fuel. Submerge the slide in the solution for a day, and I'll almost guarantee it will walk out by itself. The more it's seized use the thinned solution. For a store bought solution just about any penetrating oil will perform better than WD40.
Are you sure the extractor claw isn't grabbing the breech face?



























