Plastics are known for specific properties that are rarely found in other materials. Lightness, excellent shock absorber, corrosion resistance, and low thermal and electrical conductivities are inclusive. Wastes released from plastic products are becoming highly alarming and a threat to human life. Conversion of expired plastic products, whether thermoset or thermoplastic, into raw materials for green production of energy materials forms one of the solutions to address the plastic issues. Interest in agriculture for producing food to meet the needs of the increasing human population results in various food items across the globe. Nonedible components of agricultural production, which are potential sources of materials, are not fully developed. This can be linked to industrialization making fossil resources available as a source of carbon, heat, and or energy production. Tapping fossil resources disturbs ecological balances and has a link with hazards such as earthquakes. Fossil resources are extinct or non-renewable. They are unlike agricultural productions which release a huge amount of wastes annually or biannually with little or no economic values. Improper management of agricultural wastes is a potential source of human health impact. Recent development is the processing of agricultural wastes into nanoparticles and or fibers, which are used as reinforcement in new and recycled plastics for nanocomposites fabrication. This chapter discusses various plastics, their applications, recycling of expired plastic products, synthesis of nanoparticles from agricultural wastes, development of polymeric nanocomposites, their structures, properties, and applications.