Nearly everyone has left a plastic item too close to the oven or stove (or a pot or pan on those appliances) at some point. The result is usually a fairly big nuisance, but the good news is that generally the situation is not life-threatening. However, before you use the item again, you will need to clean that melted plastic off.
Let the plastic cool. Although this may seem counterproductive, after plastic has melted to a hot surface, you run the risk of incurring serious burns if you try to remove the plastic before it is cool. Simply put the hot item in a safe place to cool, or turn off the heat if you are dealing with an oven or stove. Wait until everything has cooled to clean melted plastic.
Treat plastic melted onto a stove burner or oven rack with rubbing alcohol. Never try to clean any hot surface until it has cooled completely. Saturate a cleaning rag with rubbing alcohol, and place it on top of the plastic. The rubbing alcohol will interact with the plastic and create a gooey mess. You can clean the mess off by rubbing the area with the treated rag.
Remove melted plastic from the sides of pots and pans with baking soda. Boil about 1 inch of water in the pot or pan. If the plastic is higher up on the side of the item, then you will need to boil more water. Add 1 tsp. of baking soda for each inch of water. After the water reaches a boil, turn it down to simmer and scrape off the melted plastic using a spatula. It should come off in one piece. You can also use this technique to remove stubborn plastic from the bottom of the pan, but do not boil the water, simply simmer it to avoid burning the plastic more thoroughly onto the bottom of the pan.
Clean the item or surface thoroughly before you use it again. For the stove top or oven, use white vinegar and water. For the pots and pans, you can use a mild detergent to clean the entire item before you use it again.