Abstract: A major portion, preferably a substantial portion, of the coke precursors may be removed from atmospheric and vacuum resids having a Conradson carbon residue of at least about 10 wt. % by selectively removing the components of said feedstock which have an overall Hildebrand solubility parameter greater than 9.0 and a complexing solubility parameter greater than 1.3, such that there results a coke precursor rich fraction containing components having the requisite solubility parameters and a coke precursor depleted fraction. Each fraction may then be processed separately. Segregation of coke precursors by removing the components having the requisite solubility parameters also results in an enhanced yield of useable liquid hydrocarbons relative to that obtained using conventional separation processes.