Turn off the oven and let it cool completely
Open windows and ventilate the area
Remove oven racks and loose debris
Wear gloves and a mask if needed
Scrape off hardened plastic gently with a plastic scraper or wooden spatula
Use a soft cloth with warm soapy water to wipe away residue
Apply baking soda paste to stubborn spots and let it sit briefly
Wipe again with a damp cloth
For remaining residue, use a non-abrasive oven-safe cleaner
Clean the oven racks separately with warm soapy water
Run the oven empty at low heat only if the manufacturer recommends it
Avoid using metal tools that can scratch the oven surface
Avoid turning the oven on until all plastic is removed
If the plastic is heavily melted or inside heating elements, contact a professional