One of the fastest ways to ruin a nonstick surface is to overheat oil to the point that it smokes and leaves a hard, dark, difficult-to-clean film on the pan. Nonstick pans are especially vulnerable since we tend to use less oil in them, and less oil heats up faster. Plus, the dark surface makes it hard to see what’s happening with the oil. To avoid carbonized oil buildup, use refined vegetable oils, which tolerate higher degrees of heat. Generally, canola, safflower, sunflower, soy, and corn oils won’t begin to smoke until they reach 420ºF. Olive oil has a lower smoke point of around 360º to 380ºF. (Frying temperatures are typically around 325º to 375ºF.)