Abstract: The disclosure relates to fuel additive compositions including heavy paraffinic distillates and lighter petroleum distillates, in particular with the heavy paraffinic distillates including a mixture of hydrotreated and/or saturated components and solvent-dewaxed and/or branched components. The disclosure further relates to fuel compositions including the fuel additive composition and a liquid or solid combustible fuel. Related methods include methods of making the fuel compositions and methods of burning the fuel compositions. The resulting fuel compositions have several improved combustion properties such as improved combustion efficiency, improved combustion energy/calorie content, reduced sulfur generation, and reduced ash generation.