A weak-acid extraction technique for inductively coupled plasma spectroscopy (ICP) was recently advocated as an inexpensive, highly precise method of chemical characterization of archaeological ceramics. We critically evaluate this approach on the basis of a large sample of Southwestern ceramics which were analysed both by weak-acid extraction ICP and neutron activation analysis. The comparison of the two data sets shows significant compositional discrepancies that lead to widely divergent archaeological interpretations.