DESCRIPTORS: *Soldering fluxes, Test methods, Sampling, Specifications, Corrosion, Additives, Detection. To establish the necessity of including flux from cored solders in qualification inspections, activated and nonactivated liquid external fluxes and cored solders containing fluxes of the same composition were studied. An effective method for removing flux from the cored solder, the condensation-extraction method, proved effective. Flux extracts from cored solders and equivalent liquid external fluxes were subjected to test methods of the Materials and Perform-ANCE CATEGORIES IN Spec MIL-F-14256b. Evaluation of the results showed that flux extracts performed in the same manner as the liquid external flux in all but 3 test methods: (1) acid number; (2) dryness; and (3) resistivity of water extract. A substitute for the complicated vacuumdeposited-copper corrosion test using electroplated Cu on ferrotype panels was found. Methods for detecting the presence of the flux additives, metallic salts and maleic anhydride, were established.