An alternative strategy for plastic waste management, known as upcycling, uses chemical methods to decompose plastics into constitutive chemical species that can be upgraded to obtain value-added products. Chemical upcycling pathways are more complex than mechanical recycling ones, as they involve complex sequences of processing steps; however, they can be more scalable, as they can process a broader range of plastic waste streams. The chemical upcycling pathway that we analyze here is a thermo-chemical pathway that begins with the sorting and purification of plastic waste fractions of common recyclable waste streams at material recovery facilities (MRFs) and plastic reprocessing facilities (PRFs). Sorted plastic waste (in the form of a mixed bale) undergo a series of chemical conversions including pyrolysis and steam cracking to arrive at pure plastic monomers (olefins), which can finally be repolymerized into products with the same original properties as virgin plastics (here, we target low-density polyethylene and polypropylene, which are two of the most dominant plastics . The ability of going back to original virgin plastics enables the creation of a circular plastics economy.