Egregoros

Well sir, we can't take any action when we don't even know if Nigerians melt.

Apply enough heat they'll melt or at least incinerate

You need a pressure vessel with about 15 atmospheres. I forget the temperature and there's probably a lot of offgassing you also have to deal with. The products are more like diesel than asphalt or tar, though.

Imagine the smell. No thanks.