Updated project metadata. Ceramic vessels were used to cook fish/duck/black grouse, and proteomic studies were conducted on the ceramics to study how the choice of various database can affect the species identification and whether they can allow us to differentiate between fish and bird processing in ceramic vessels. We also employed a novel urea-GuHCl DES as the extraction reagent, and compared its efficiency with the conventional 6M GuHCl used for protein extraction (data available in project PXD027720). The samples used were same as the samples used in Peoject PXD027720, with a urea-GuHCl DES used as the extraction reagent instead of 6M GuHCl solution.