Plastics are primarily single-use and are disposed of in municipal solid waste landfills at the end of their life cycle. Such plastic waste undergoes partial degradation and results in the leaching of persistent contaminants such as surfactants, plasticizers, fire retardants, micro(nano)plastics, nanomaterials, etc., which are of great concern. Hence, the recovery and utilization of landfill-mined plastic waste (LMPW) and fresh municipal plastics waste (FMPW) is mandatory. Though thermal treatment techniques are widely used, they could treat only ≈8% of the total plastic waste generated due to their demand for pollution control measures which have been proven expensive. In this context, mechanical recycling, which allows the conversion of plastic waste into composites for different engineering applications, has been investigated by adding appropriate fillers. However, before creating composites, a comprehensive understanding of mechanically recycled waste plastics alone (read as blends) is necessary. This becomes important because most plastics used in domestic and industrial activities are significantly augmented by adding organic or inorganic constituents to achieve the target properties. Hence, the perpetual question, ‘whether the recycled polymer blends obtained from FMPW and LMPW are composites’ remains unanswered. This is key to decide upon the optimal dosage of the fillers to be used for achieving the target properties of the composites. To address these issues, extensive investigations were conducted to establish the overall characteristics of different blends obtained from FMPW and LMPW. Furthermore, after removing the polymeric component, the residues obtained from these blends were extensively characterized. This exercise revealed that the residues mainly constitute CaCO3, TiO2, and SiO2, which are either intentionally added while manufacturing virgin plastics or are due to contamination. It was also observed that the mechanical properties of the blends get enhanced due to the presence of residues, which indicates that these are composites and not blends.