Rogues who carried snuff or dust in their pockets, which they threw into the eyes of any person they intended to rob; and running away, their accomplices (pretending to assist and pity the half-blinded person) took that opportunity of plundering him.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
To Amuse * AnabaptistNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes