How to clean melted plastic from oven

Ugh. Obviously, the oven isn't usable like that. Well, if you can't pry it up without damaging the enamel, or the surface isn't flat enough to scrape it off with a razor blade, the next step is probably to see if a little temperature might loosen it up. I'm guessing that a freezing attack like gum remover would shatter the enamel, so warmth without enough heat to produce a bunch of fumes might loosen it up. If that doesn't work, if the package says what kind of plastic it is, then you can try a solvent for that plastic. My guess is that it's mylar, which is pretty resistant to solvents. If it is, this chart says that Sodium Hydroxide (Lye) will attack mylar, and that's a common ingredient in oven cleaner. I can't find any information that discusses the safety of this interaction but I'd consider it if I had good ventilation... but it would probably be a good idea to check with a chemist.

I did it by using ice to make the plastic rigid. Then I used a long, dull knife to pry it off. No damage to oven. But, mine was a melted electronic thermometer not meant for an oven.