Abstract: Improved noncatalytic nonreactive alumina-silica solid for removing carbonaceous and metallic contaminants including nickel and vanadium from hydrocarbon feedstock by short term, high temperature contact comprises mullite and crystalline silica. In the decarbonizing and demetallizing process, impurities are deposited on the particles of the solid and the major portion of the feedstock is vaporized. After burning carbonaceous deposit from the particles, the hot particles containing nickel and vanadium are recycled into contact with incoming charges of contaminated feedstock. Periodically metals are removed from coke-depleted particles by extraction with a mineral acid at elevated temperature without dissolving or otherwise destroying the alumina-silica particles. The particles are then reintroduced into the system.