Enhanced Landfill Mining (ELFM) is considered a remediating strategy for old dumpsites and landfills in an environmentally sound manner. However, due to differences in MSW definitions and less strict regulations and controls in the past, hazardous impurities from household waste and IW from different enterprises could have entered the MSW system, causing major research challenges in landfill mining. Not only the uncertainty of whether hazardous materials are present inside a landfill is a risk to ELFM, but also the material composition itself. Both strongly influence the type of pretreatment needed, as well as the quality of the material to recover. Even if there is a record of the type of materials buried inside a landfill, still landfill technology has a direct impact on the composition of landfilled waste. This may imply that some municipalities have a higher CDW rate in their MSW landfills than others. However, the main reason why CDW ended in landfills is due to its large amounts, properties (bulky and heavy), and simply, because it was said to have no value.