Per Schimmel's U.S. State-Issued Sales Tax Tokens, Mississippi issued three different series of tax tokens. The ones used 1936-41 were aluminum for the 1 mill denomination and brass for the 5 mill. Yours are the former. Then in 1942 they issued white fiber and grey fiber 1 mill and red-brown fiber 5 mill tokens. Finally the 1943-52 series was off-white plastic and snow white plastic 1 mill and blue plastic 5 mills.
John in the Great 208