Still, the stuff is still basically hydrocarbons either way - you should be able to break it down to it's constituents and refine it to something indistinguishable from the normal feed stock. Woukd it be horrendously energy intensive ? Most likely! But definitely doable.

BTW, this is why I'm skeptical to efforts to fix the environment just by saving energy. Sure, it should not be wasted but if we want to fix all damage that has veen done while still providing adequate standards of living for everyone, we beed to produce much much moore energy than we do now & do it in a clean way - most likely mega massive solar on enything, lots of nuclear fission and possibly massed off shore wind as well. Ideally backed by storage if/where possible.

Together with megaproject scale waste processing it should be possible to cleanup (and reuse!) all the old stuff while also handling all the new stuff comming in.

And the end result would be a nice clean plabet yet again, but this time with very robust energy and industrial infrastructure ready to face future challenges - or disasters!

Sounds like something one can aspire for rather than all the doom and gloom one sees some days.