Green’s Dictionary of Slang

that which is empty, usu. of an empty bottle but see cite 1855.

1830		J.B. Skillman N.Y. Police Reports 1: I can say of myself / [...] /I embarked in an expensive and hazardous busainess, / And, / Here I am, / With pockets / M.T.
1840		London Mag. Feb. 66/2: “The Works of Sir E. L. Bulwer, Barren-head, M.P., M.A., M (a) D., M.T (empty), M.(u) F.(f), M.O.P., &c. &c.; a new and beauti- fully illustrated edition.
1855		Delhi Sketch Bk 1 Dec. 140/2: Before the grate is M T (empty) / Be sure to put the : (coal on).
1859		Wkly Varieties (Boston, MA) 29 Oct. 8/4: Con. Why is Soapy Haskell’s head like two ltters of the alphabet? Ans. Because it’s M.T.
1864, 1867, 1870		Hotten Sl. Dict.
1881		Trumble Sl. Dict. (1890).
1933		‘William Juniper’ True Drunkard’s Delight 236: An M.T. is an empty bottle, one bearing Moll Thompson’s mark, i.e. M.T.
1937–84		Partridge DSUE (1984) 710: [...] from ca. 1858.