Green’s Dictionary of Slang

(US Und.) a thug.

1950		Where the Sidewalk Ends [film script] Hoods, dusters, mugs — a lot of nickel rats.
1952		L. Hughes Laughing to Keep from Crying 61: Lemme tell you ’bout the last duster that crossed my path. He were an Al Capone – machine gun and all – and I just mowed him down with my little thirty-two on a forty-four frame.