The article proposes a method for separating a mixture of plastic waste using a flotation method. The subject of the study was mixed plastics, derived from post-consumer car headlights recovered from the dismantling of end-of-life vehicles. A three-stage separation was carried out, where the specific density of the flotation medium was a variable parameter. The process was carried out using three solutions, i.e. 25% potassium hydroxide (KOH) solution with a density of 1.172 g/cm3, 17% KOH solution with a density of 1.113 g/cm3 and 11% KOH solution with a density of 1.061 g/cm3. As a result of the separation process, the initial mixture of plastics was separated into four fractions, containing materials differing in specific density. Quantitative analysis was carried out and material identification of the obtained fractions was performed using Fourier transform infrared spectroscopy (FTIR). Based on the results obtained, it was shown that the separation by flotation method can be successfully applied in the process of separating polymer waste, derived from the automotive industry. The carried out research is in line with the assumptions of the circular economy of plastics, as well as contributes to the development of ecological separation processes, supporting the achievement of global sustainable development goals through the reuse of resources, as well as the reduction of waste.