Abstract: A method for cleaning an exhaust gas comprising a base gas and at least one toxic component selected from the group consisting of arsine, phosphine, diborane and hydrogen selenide is disclosed. The method comprises contacting the exhaust gas with a molded cleaning agent having a composition consisting essentially of (1) cupric oxide, (2) manganese dioxide, and (3) at least one metal oxide selected from the group consisting of silicon oxide, aluminum oxide and zinc oxide and having a density of from 0.6 to 1.5 g/ml, said composition having a metal atomic ratio M/(M+Cu+Mn) in the range of from 0.02 to 0.70 and a metal atomic ratio Cu/(Cu+Mn) in the range of from 0.1 to 0.9; wherein Cu represents a number of gram atom of copper; Mn represents a number of gram atom of manganese; and M represents a total number of gram atom of silicon, aluminum and/or zinc, to remove the toxic component from the exhaust gas. The method is effective even at low temperatures below 10.degree. C.

Abstract: A method for cleaning a gas containing at least one toxic component selected from the group consisting of arsine, phosphine, monosilane, diborane, and hydrogen selenide, which comprises contacting the gas with a cleaning agent containing a molded composition comprising (1) manganese dioxide and (2) cupric oxide, having deposited thereon (3) a silver compound, wherein the weight ratio of cupric oxide to manganese dioxide ranges from 0.2 to 1.2 and the amount of the deposited silver compound ranges from 0.01 to 10.5% by weight based on the cleaning agent. By the cleaning method, the toxic component can be removed from a gas, e.g., air, at high efficiency and at a high rate even in case of sudden leakage of the toxic component out of a bomb.