Always use a non-aerosol, high heat oil. Many cooking sprays contain lecithin. Lecithin can destroy the non-stick surface of your Ninja Foodi Grill and inserts. I prefer to use avocado oil because it does not have much flavor at all and is safer to use because it does not have lecithin. Other high heat oils are peanut, canola, sunflower, and sesame oil. Many of these oils can be found at your local grocery store in a non-aerosol spray can. Otherwise, you can buy an oil mister off of Amazon fairly inexpensively.