The good thing is circular economy has the power to create identification through success as well as through a feeling of purpose and belonging for everyone acting in the plastics industry! The consumption of plastic is increasing steadily due to the worldwide population growth resulting therefore in a higher demand of plastic products. As the price for plastic material is low and plastic waste is not regarded as a valuable product, the consequence is a global plastic crisis, in which plastic waste does not enter a circular economy but a linear economy with undefined leakages. Nevertheless, from the industrial point of view, polymer recycling is already highly advanced. The different recycling process steps within the circular economy consist of collecting the waste, rough sorting between main plastics, shredding, washing and drying, flake sorting, and remelting by extrusion. Extruders play an essential role in the different plastic waste recycling types: mechanical, solvent-based, and chemical recycling. Mechanical recycling consists of melting the polymer, degassing, and filtration enabled by extrusion and filtering devices. Solvent-based recycling follows a similar principle in the first stage. Additional reactor units are needed to dissolve the target material by solvents. After the reactor step, degassing can be realized by extruder systems as well. One form of chemical recycling uses depolymerization to convert the feedstock waste polymer into monomers, which can be transformed back into a polymer. All these forms of extrusion related recycling are described within this chapter.