Actually, that's incorrect. Any form of oil, be it olive, canola, corn, sunflower, or milkfat, will gladly bond with THC. Margarine will work just as well as real butter. In fact, if you do use real butter, the resulting solids are not butter anymore, just saturated fats. Butter is part oil, part water, and part protein. You can make cannabis olive oil for salad dressing if you want, just simmer some oil with water in a pan, and make sure you don't let all the water evaporate. Unfortunately, since olive oil doesn't solidify like milkfat does, it's harder to strain and store the product. But it's just as worthwhile, trust me