Energy-dispersive X-ray fluorescence spectrometry (EDX) is a widely used modern elemental analysis method. Most of the commercially produced EDX spectrometers cannot determine elements with atomic numbers below 11 (sodium). The EDX spectra contain scattering components and their intensity depends on the elemental composition and physical properties of the samples. The use of scattering as an analytical signal provides the opportunity to determine the integral characteristics of various samples. Since the light elements (with atomic numbers <11) also contribute to the scattering, it is possible to indirectly quantify these elements. In this study we demonstrate the use of X-ray scattering signals and chemometric tools to assess the physical properties and quantify the carbon, oxygen, and hydrogen content of various plastics.