In relation to a cut and pull operation, a nuclear tool may be used for evaluating the composition of materials located behind a pipe lining the wellbore. More specifically, a downhole method may include emitting gamma rays into the pipe and the material from a source of a nuclear tool disposed in the wellbore; detecting gamma radiation scattered back from the pipe and the material with a detector of the nuclear tool; determining a high-energy range and a low-energy range for the gamma radiation; measuring count rates of the gamma radiation in the high-energy range (CRH) and the low-energy range (CRL); performing an analysis of (1) the CRH relative to (2) the CRL; and determining a compositional equivalent for the material based on the analysis.