Microplastic pollution has risen to such a level that concerns are being raised regarding its consequences on the environment, especially the marine environment. Understanding microplastic pollution temporal dynamics is critical but requires time-series. However, concerns about microplastic pollution being recent, long term monitoring programs have only started very recently and remain scarce. Natural History Collections that represent archives from the past can constitute time-series. Although underused, they have evinced their success to study various stressors including pollutants, in particular when using bioindicators. Bioindicator species should be defined with regards to the studied environmental disturbance according to established criteria. Those criteria include occurring frequently, being sensitive to the pollutant, and allowing, via their monitoring, a summary of the pollutant’s impacts at molecular, organismal or population levels. However, to analyse bioindicator species in Natural History Collection time-series, several specificities need to be considered. Starting from a review of articles that utilised such collections to study microplastic evolution in a given ecosystem, and focusing on their methodologies, we emphasise Natural History Collection features that need to be taken into account when choosing the most adequate taxon and extraction techniques. In particular we discuss four collection features: sampling heterogeneity, taxonomic misidentification, past environmental contamination and specimen destruction and provide leads to address these issues. We believe that combining the concept of bioindicator with valuable samples from Natural History Collections is of particular interest to monitor past microplastic pollution and better predict future trends. This constitutes a necessary step in assessing the basal level and the continuing evolution of this ever-increasing pollution.