Green’s Dictionary of Slang

(US) to work as a commercial traveller.

1938		M. Rand ‘Clip-Joint Chisellers’ in Ten Story Gang Aug. 🌐 The rest of his time was spent drumming his wares in the New England territory.
1949		A. Miller Death of a Salesman 81: A salesman eighty-four years old, and he’d drummed merchandise in thirty-one states.
1960, 1975		Wentworth & Flexner DAS.
1986		L. Heinemann Paco’s Story (1987) 61: Salesmen drumming Snap-On tools and CBs, Bibles and other inspirational literature.