The new library cleaning pipeline was run on the GNPS public mass spectral library. A YAML file and processing report were automatically generated. The processing report can be found in Supplementary Table . Before cleaning, the GNPS library contained 500569 spectra. Figure gives a visual overview of the number of spectra affected by the different filters. Figure shows two examples of metadata of real spectra stored in the GNPS library and illustrates the effects and importance of metadata curation via matchms.