Turn off the oven and let it cool completely
Open windows and turn on ventilation
Remove oven racks and loose debris
Wear gloves
Scrape off hardened plastic with a plastic scraper or wooden spatula
Use ice in a bag to harden stubborn plastic before scraping
Apply baking soda paste to remaining residue
Wipe with a damp cloth
Use vinegar or mild dish soap for final cleaning
Clean removable parts separately
Run the oven on low heat briefly after cleaning to remove odors
Repeat if needed until all residue is gone