Abstract: A strontium colloid system is introduced into a hydrocarbon conversion process to suppress the harmful effects of one or more metal contaminants in the hydrocarbon feedstock on the active component(s) of the catalyst used in said process. The strontium compound in the colloid system reacts with or traps the metal contaminants before they contact the active component(s) of said catalyst, thereby reducing catalyst deactivation, coke make and hydrogen production relative to that obtained had said compound been introduced into the process in non-colloid form. In a preferred embodiment, the strontium colloid system is introduced into the reaction zone of said process and, preferably, with at least a portion of the hydrocarbon feedstock to said process.