Plastic Safe

What’s the best way to melt plastic in an environmentally-safe way?

I’m wondering because one of my friends wants to produce something made of plastic so he wants to melt it but in an effective, quick and easy way and also environmentally safe. Any suggestions? Thanks in advance.
i dont know what he wants to produce, I will ask him. Thanks for the suggestions.

VERY IMPORTANT : DON´T DO IT ! ! ! !

I am not kidding, dioxine which you would get out of PVC (Vinyl) is used as a reference for toxicity to the human body !

It stays in your body for 40 years and is extremely dangerous.

Unless you are precisely able to identify plastics and sort them and have a degree in polymer chemistry don´t do it !

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