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
Step 1. Place the pan in the freezer
Let it cool for at least a couple of hours to harden the plastic.
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.
Step 3. Remove the pan from the freezer
Make sure the plastic has hardened.
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.
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.
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.