ISO 1407:2011 specifies four methods for the quantitative determination of the material extractable from raw rubbers, both natural and synthetic; two of the methods are also applicable to the unvulcanized and vulcanized compounds of raw rubbers. Method A measures the mass of the solvent extract, after evaporation of the solvent, relative to the mass of the original test portion. Method B measures the difference in the mass of the test portion before and after extraction. Method C, which is for raw rubbers only, measures the difference in the mass of the test portion before and after extraction using boiling solvent. Method D, which is for raw rubbers only, measures the difference in the mass of the test portion before and after extraction relative to the mass of the original test portion. Recommendations as to the solvent most appropriate for each type of rubber are given in an annex.