Fireplace residue is composed of three main components: ASH, SOOT, and ASHES. ASH is the lightest of the three, consisting of small particles of mineral matter that are left behind after combustion. SOOT is a black, powdery substance that is created when fuel does not burn completely. ASHES are the remains of burned material, such as wood or coal, that have been reduced to a fine powder. All three of these components are common byproducts of burning fuel in a fireplace.