In order to study the behaviour of trace impurities during aqueous dissolution of a sample, aluminium and nickel-based alloys containing 10(-4)-1% Ir, Os or Ru were used. Yields of chemical separations such as distillation and ion-exchange were chosen as dissolution criteria. Dissolution of aluminium samples leads to precipitation of the three impurities. The Os and Ru precipitates can afterwards be dissolved by an oxidation procedure, in contrast to commercial powders of these elements. This behaviour may be explained in terms of the small grain-size of the precipitates. The indium precipitates cannot be dissolved, which prevents quantitative separation of this element from an aluminium matrix. In the case of nickel alloys, these three impurities are dissolved and can be quantitatively separated.