There is quite interesting Israeli startup Ubq[1] claiming it can recycle [2] greasy plastics into the material usable for further plastics manufacturing.
It’s not hard to come up with a process that can recycle anything organic into any petrochemical via Fischer Tropsch. What’s difficult is doing it economically.
[1] https://www.ubqmaterials.com/
[2] https://www.washingtonpost.com/graphics/2019/climate-solutio...