If your skillet or frying pan has become warped, there are a few methods you can try to flatten it:
Heat and cool method: Place the warped pan on a stovetop burner set to medium heat. Allow the pan to heat up for a few minutes until it becomes hot. Then, using oven mitts or pot holders, carefully remove the pan from the heat and place it on a heat-resistant surface. Quickly place a heavy, flat object (such as a cast iron skillet or a baking sheet weighted with oven-safe weights) on top of the warped area. The weight should help to flatten the pan as it cools down. Allow the pan to cool completely before removing the weight.
Hammering method: This method requires caution and should be used as a last resort for pans with severe warping. Place the warped pan on a hard surface, such as a concrete floor or a sturdy workbench. Using a rubber mallet or a wooden block and a regular hammer, gently tap the warped area from the underside of the pan. Start with light taps and gradually increase the force until the pan starts to flatten. Be careful not to apply too much force, as it can cause further damage to the pan. Flip the pan over and check for progress periodically, adjusting your tapping as needed.
It's important to note that these methods may not always completely restore a heavily warped pan to its original flat shape. Warping can occur due to various factors, including uneven heating or rapid temperature changes. Additionally, if the pan is made of thin or poor-quality material, it may be more prone to warping. If the warping is severe and affects the pan's functionality, it may be best to consider replacing it.