Abstract: A method of regenerating used particulate contaminant-removing material, such as iron oxide or iron sulfide, that has been used to remove a contaminant, such as arsenic, from a synthetic hydrocarbonaceous feed and effect deposition of the contaminant within the material, characterized by a multi-step process as follows: (1) the used, or spent, contaminant-removing material is intimately contacted with a sulfur-containing material, such as hydrogen sulfide or sulfur, in an inert atmosphere of non-oxidizing fluid and at elevated temperature; (2) the contaminant deposited in the contaminant-removing material is reacted with the sulfur in the sulfur-containing material at the elevated temperature and the resulting sulfides of the contaminant; for example, arsenic sulfides; are converted to gaseous form to separate them from the regenerated contaminant-removing material; and (3) the sulfides of the contaminant are condensed and oxidized to form the oxides of the contaminant; for example, arsenic oxides.