This manuscript addresses the “classical” problem of estimating electrical conductivity of metals. The novel contribution of this work is the use of a new set of features, namely time constants of the source-free response in a pulsed eddy current testing (PECT) experiment. Time constants characterize the source-free response and increase monotonically with the electrical conductivity of the specimen. Time constants form a particularly important set of features because they do not depend upon the probing system and, hence, they are not sensitive to probe lift-off and tilting which are responsible for significant experimental errors.