Under the era of circular economy, the deposit-refund system (DRS) for e.g. polyethylene terephthalate (PET) is thought to be a good choice to achieve a more structured plastic recycling. The present research has the aim to make a comprehensive description and a practical guideline in order to evaluate how collection and separation system influence the quality and efficiency of mechanical recycling of PET. The DRS has been symbolized by manually collected bottles with (BCL) and without (B) caps and labels. Samples have been given from the selective income (SI) and the sorting residue (SR) of a manual selective waste sorting plant and PET fraction of refuse derived fuel (RDF). Based on preliminary qualification results such as melt flow indices (MFI), PET bottles are worth selecting into the main colours like water clear, blue, and all the others together, referred to as PET-A, PET-B, and PET-D fractions of the sorting plant. The SR seemed to be a beneficial raw material for PET recycling as both mechanical and rheological properties were proper enough. PET separated from the Mechanical Biological Treatment (MBT) plant as RDF showed the worst processing and mechanical properties, but both can be improved with deeper precleaning. X-ray tomography (CT) scans have shown a correlation between the source of waste and the gas void structure which influence the macroscopic mechanical properties.