Recently, a novel thermoforming process involving induction heating of tin interlayers to create ‘lubricated blanks’ using low viscosity molten tin was demonstrated (“iMelt”) (Harrison et al., 2020). Important to the success of the method is expulsion of the tin interlayer from the blank using a multi-step thermoforming operation. Approaches to characterise the quantity of residual tin and impact on the mechanical properties of the formed parts are established. 3D x-ray CT was used to accurately determine residual tin content while results from 2D x-ray scanning were shown to be highly-correlated with the 3D data and therefore can be a faster, low-cost alternative. After gradual refinement of the process, it was shown that residual tin volumes as low as 1.6 % were achievable in flat laminates. Compared to reference samples consolidated without tin, the remnant tin caused a reduction in yield strength and flexural stiffness, while producing comparable ultimate interlaminar shear strength.