If you accidentally left plastic in a hot pan while you were cooking, it probably melted on the cooking surface. It is a real annoyance to have to go and buy a new one for this very small, and solvable, mistake. Wouldn't it be much better to find out how to remove melted plastic from the pan?
Steps
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Step 1. Place the pan in the freezer
Let it cool for at least a couple of hours to harden the plastic.
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Step 2. In the meantime, look for an object that won't damage the surface of the pan, such as a piece of wood, a plastic mallet, and so on
You can use any heavy object, but it should be softer than the metal in the pan.
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Step 3. Remove the pan from the freezer
Make sure the plastic has hardened.
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Step 4. Place the pan upside down on a flat surface
Better to perform this procedure on the floor than on the kitchen cabinets. Whichever surface you choose, make sure it can withstand the force you will exert.
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Step 5. Gently hit the bottom of the pan on the point where the plastic melted using the object chosen earlier
Don't hit too hard, or you risk damaging it.
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Step 6. Repeat Step 5 if the procedure fails, but this time with less delicacy
Try to be patient. Gradually the plastic will come off the pan. Once disposed of, wash it before using it again.