**3. Conclusions**

This chapter briefly presents all methods that are used nowadays for plastic recycling, including primary recycling, energy recovery, mechanical recycling, and chemical recycling. The advantages and disadvantages of each method are discussed. Emphasis though is given on chemical recycling and mainly, pyrolysis, due to its many benefits, which are fully described. Furthermore, three case studies that involve some difficulties in plastic recycling are thoroughly investigated. The first one includes the case of polymeric blends, where the coexistence of different plastic materials makes their recycling more difficult. The second one is focused on the recycling of plastics that come from multilayer packaging. The main obstacle in this case lies in the fact that multilayer packaging comprises various, different materials, such as paper and metals, apart from the plastics, so extra attention is required for their separation and recycling. The last case study that is presented here is that of brominated flameretarded plastics from WEEE, since in such cases direct recycling is not that easy due to the formation of undesirable brominated compounds and more often than not a pretreatment step prior to their recycling is necessary. Taking into account the mentioned difficulties, the aim of this chapter is to present and analyze various recent literature data along with suggestions on how to overcome the mentioned problems.
