Design Engineers take use of various tools and methods to aid on decision making on end-of-life of products, including techniques such as Design for Disassembly, Design for Environment, Design for Recycling, Design for End of Life, and so on. Among the Design for Recycling techniques there are specific tools regarding to the reprocess of product components, including some compatibility tables for plastic materials. These tables list possibilities of compatibility of commonly employed plastics, however not providing further information about how compatible they are. On the other hand, material engineers study reprocessing strategies like polymer mixture in a more specific way, evaluating all blend properties. So, to the polymer engineering, compatibility is a technological term that is related to desired final properties of the mixture. Furthermore, the wide range of plastic grades available implies greater difficulties on using these tables due to the presence of additives in some grades, such as fillers, fibber glass and flame retardants. The limitations of these compatibility tables are evaluated in this paper and some background is provided for developing a new compatibility table. Compatibility concept is evaluated both under the view of the design and the polymer engineering, different polymer mixtures and blends are gathered from literature, and a new compatibility table, based on compatibility concept adopted by materials engineering, is presented for some commonly employed polymers.