Green’s Dictionary of Slang

1. a derog. term for a black person; also a nickname.

1894		Truth (Sydney) 20 May. 1/6: There are ‘Tarpots,’ ‘Charcoals,’ and ‘Day and Martins’ all over the continent.
1935		C. Drew ‘The Bone-Head’ in Bulletin 6 May 31/3: Gradually the nig. crept up on our bloke. He caught him when the pair were about twenty yards from the tape, and the crowd [...] yells. ‘Come on, Charcoal’.
1992		D. Pinckney High Cotton (1993) 140: I would come to no good among the no accounts, burrheads, shines, smokes, charcoals, dinges, coons, monkeys, jungle bunnies, jigaboos, spagingy-spagades, moleskins, California rollers, Murphy dogs, and diamond switchers.

2. as used by a black person, thus not derog.

1926		Van Vechten Nigger Heaven 13: Blues, smokes, dinges, charcoals, chocolate browns, shines, and jigs.
1931		N. Van Patten ‘Vocab. of the Amer. Negro’ in AS VII:1 27: charcoal. V. n. Negro.