We need food, water, and air to live while plastics are necessary for our comfort. Despite the calls on banning plastics from every nook and corner of our society, we currently have no alternative to plastics. It is therefore of utmost importance to embrace the concepts of circular economy and call for responsible uses of plastics articles. An important aspect of circular economy is upcycling of plastics wastes. Responsible usage alone is not enough to lessen the burden on our already harmed environment and ecosystems. In conjunction, the scientific principles of upcycling of plastics wastes must be developed. In this context, we are currently exploring the principles behind conversion of polyolefin wastes into useful, upcycled and reusable products. We base our work on polyolefins due to its high volume and lowest price among all plastics and the strongest potential gain in upcycling. Specifically, our research focuses on two directions. In our first project, we convert polyolefin wastes into 3D-printed articles via manipulation of melting profile and rheological parameters. In our second project, high density polyethylene and isotactic polypropylene wastes are converted into highly porous gels and aerogel materials for upcycled commodity applications as impact pads and as oil absorbing media. Some of the key scientific developments in rheology, gelation kinetics, and pore architecture designs will be shared.