In the 19th century, significant linen and leather imitation products were invented using cellulose nitrate-coated fabrics, including celluloid detachable collars and Fabrikoid artificial leather, now preserved in the Hagley Museum and Library, USA. Using optical microscopy, µRaman, and µFourier Transformed Infrared spectroscopies, this study highlights the need for characterizing the heterogeneity of these materials at the microscale. While the detachable collars have well-preserved fabric coatings composed of cellulose nitrate, camphor, anatase (TiO2), and carbon-based particles, Fabrikoid’s pigmented cellulose nitrate-castor oil systems show problems. Our molecular data align with a 1922 report on Fabrikoid degradation, revealing free fatty acids and carboxylates formed due to oil oxidation. This is concerning as these materials were used until the 1960s, demonstrated by the analysis of objects from the National Museum of Costumes in Portugal. Future studies should address the compatibility of cellulose nitrate with fatty acids and the reactivity of additives in these systems.