A method is provided for separating offgas from solid and/or liquid reaction products in the combustion of a metal M selected from alkali metals, alkaline earth metals, Al and Zn, and mixtures thereof, with a combustion gas. In a reaction step, the combustion gas is combusted with the metal M, forming offgas and further solid and/or liquid reaction products, and, in a separation step, the offgas is separated from the solid and/or liquid reaction products. In the separation step, a carrier gas is additionally added and the carrier gas is removed as a mixture with the offgas.