The new materials of twentieth-century technology provided both the means and the inspiration for the three-dimensional works of the Constructivists. Plastic, which was particularly versatile, was employed frequently by Naum Gabo and his brother Antoine Pevsner to realise the innovative sculptural forms advocated in their “Realistic Manifesto” of 1920. In Gabo’s more organic works and linear compositions of the 1930s and 1940s, it can even be postulated that the development of acrylic plastics and filaments made such works possible. However, early plastics were extremely unstable and have discoloured, warped or even decomposed over time. The author explores the effect of deterioration on various works to demonstrate the urgent need for research on early plastics to aid the conservation of these sculptures.