Using cooking spray (PAM is the most popular) is a surefire way to ruin your skillet’s nonstick coating. These products—essentially cooking oil in a can—are meant to make your pan’s surface nicely lubricated, but the problem is that oil isn’t the only ingredient. Cooking sprays also contain lecithin, which is an emulsifier, dimethyl silicone, which is an anti-foaming agent, and a propellant such as propane or butane.
Over time, the lecithin in the nonstick spray will cook onto the surface of your pan, build up, and become nearly impossible to remove. The result? See you later, skillet. The coating gets completely degraded from the spray and will no longer act as a nonstick surface.
Cookware manufacturers agree. “The use of cooking sprays is not recommended for use on non-stick cookware as cooking sprays burn at lower temperatures and will damage the non-stick coating of your product. An invisible buildup will impair the nonstick release system causing food to stick.”
~realsimple