Compositions useful for cleaning metal from a substrate or coating metal onto a substrate are described: Such compositions comprise (a) a densified carbon dioxide continuous phase; (b) a polar discrete phase in said carbon dioxide continuous phase; (c) a metal in said discrete phase (i.e., a metal removed from the substrate, or to be coated onto the substrate); (d) at least one ligand in said continuous phase, said discrete phase, or both said continuous and said discrete phase.