Extractants containing strong ligands may be used to detach unbound or weakly attached metal ions from soils, resulting in `Mobile Metal Ions' (MMI) in concentrations readily measurable by modern-day inductively coupled plasma (ICP) analytical equipment. Mobile forms of metals Cu, Pb, Zn, Ni, Cd, Au, Ag, Co and Pd can be extracted with two digestants, and in general show strong contrast over mineralization compared to background, and as compared to conventional techniques. Four case histories are examined in detail to illustrate this point. A porphyry-type base metals prospect in the west of Scotland displays MMI surface geochemistry for Cu, Pb, Ni, Cd and Au with some evidence for zoning in sympathy with the mineralization, despite the presence of a large annual rainfall, a glacial environment, and the presence of peat. At the Nepean nickel mine in Western Australia, sharp and strong MMI geochemical signatures in weathered and partly transported soils over nickel sulphide mineralization, hosted by komatiitic channel-flow rocks is evident. Given the elevated Ni content of the hosting lithologies, it is likely that the surface MMI response is due to both the channel-flow facies rocks and the mineralization, 50 m below surface. The Golden Web gold deposit, Coolgardie, Western Australia is a discovery made by application of the MMI technique. Subsequent mining established that a high correlation existed between the times 20 MMI Au Response Ratio contour, and the economic mineralized envelope, located some 17–50 m beneath. The Anococo prospect lies in a high-rainfall area of the Guyana Shield, Venezuela. Both conventional and MMI geochemistry outline the strong primary Au mineralization in the western zone, and both correlate well with trench rock-chip sample data. In the eastern part of the same prospect, MMI geochemistry produces an anomaly of sharper and higher contrast than conventional results, within a broad conventional Au anomaly located over shallow secondary enrichment zones. The sharpness and high contrast inherent in the MMI technique make it favourable as a targeting tool to facilitate discovery of mineralization in early stages of exploration programmes.