This document specifies methods for determination of the ash of polyamides, both filled and unfilled. The general procedures given in ISO 3451-1 are followed. For unfilled materials method A and method D or method C of ISO 3451-1:2019 is used. For filled and glass-fibre reinforced materials method A and method D of ISO 3451-1:2019 is used. For glass-fibre filled materials containing flame retardant, antimony trioxide, and/or other, volatilizable, additives such as pigment zinc sulfide, a modification is incorporated to remove these as volatile bromine component(s).