Abstract: Disclosed is a metal sulfide composition for use as a machining aid comprising 55.0% to 65.0% by weight of manganese, 29.0% to 36.0% by weight of sulfur, and greater than 2.0% to 10% by weight of iron. Also disclosed is a method of making the metal sulfide composition comprising mixing manganese, sulfur, and iron; initiating an exothermic reaction between the manganese and sulfur, wherein the iron component moderates and cools the exothermic reaction; forming a solid mass of manganese sulfide composition containing a portion of the iron suspended therein; and recovering the solid manganese sulfide composition. A method of using the manganese sulfide composition according to the present invention as a machining aid comprises mixing into a blend a desired metal powder with the manganese sulfide composition; spreading the blend into a metal part die; compacting the blend into the die; sintering the compacted part; and machining the sintered part.