For anyone else, like me, who has had difficulty totally stopping oil, maybe this will help. I imagine other oils are produced in a similar manner. Nothing at all left to be consider 'food'.
"How Canola Oil Is Made
How does a cruciferous seed become a uniformly odorless, almost tasteless product? It starts with huge quantities of canola seeds, which are pressed by machine at extremely high pressure to extract the oil. “Canola cakes” are left behind as a byproduct, and are essentially made of protein; but there is a portion of oil left that cannot be extracted by pressing. So the cakes are immersed in a chemical solvent to separate the last bit of oil from the protein. The remaining protein, now free of oil, is sold to farmers as feed for animals (another reason to choose grass-fed, free-range meats!).
Next, the oil is “washed” or mixed with sodium hydroxide, also known as lye. If you’ve ever worked with or around lye, then you know how caustic this material is. The lye-oil mixture is spun in a centrifuge to separate the oil from “impurities.” What that means is removing anything that would give the oil flavor, color, or other properties of whole, natural foods.
The byproducts of the lye bath, not surprisingly, are sold to soap manufacturers.
The natural wax from the canola seeds still remains in the oil at this point, giving it a cloudy appearance. To remove this wax, the oil is chilled for the wax to separate out from the liquid oil and solidify. This wax is then sold to manufacturers of margarine, shortening, and other products that contain hydrogenated fats.
The final steps involve washing, filtering, and bleaching the oil via steam injection. This creates a highly-refined, odorless, tasteless oil that consumers use to fry foods and manufacturers use to create a plethora of boxed, packaged, processed “foods.”"
http://saveourbones.com/canola-oil-good ... our-bones/