Large amounts of industrial metal containing process and waste solutions are a growing issue. In this work, we demonstrated that they could be transformed into materials of high added values such as copper-nickel nanowires (CuNi NWs) by simple chemical reduction. A thorough investigation of the parameter space was conducted. The microstructure of the obtained material was found tunable depending on the employed concentration of precursor, reducing agent, capping agent, pH, temperature, and reaction time. Moreover, the obtained product had a strong magnetic character, which enabled us to separate it from the reaction medium with ease. The results open new perspectives for materials science by proposing a new type of nanostructure: composite NWs of very promising properties, with metallic elements originating directly from industrial process solution.