I do wonder how could there be such thing as corn oil wherein fact, even i boiled corn for even over night, th?

there is no trace of even a half drop of oil left on the kettle?I do wonder how could there be such thing as corn oil wherein fact, even i boiled corn for even over night, th?
My best guess is it needs to be pressed out of the cob, or the skin of the kernals. but idk, seems like boiling should have done it though maybe you should try it with something else, maybe olives or peanuts or sunflower. it all has oil in it, maybe boiling isn't the process you need to use