If coal must be used in industry to replace oil that becomes scarce, the coal should be demineralized to get a clean, high-heating-value noncorrosive, free flowing solid fuel. Alkali leaching of coal under ambient pressure followed by acid leaching under milder conditions affords a convenient process for cleaning coal up to a degree of demineralization of 75%. The conditions for alkali-acid leaching have been optimized. Toxic mineral microconstituents are removed to give a clean coal for burning in thermal power stations or in industries. The demineralized, clean, high-heating-value coal can be used for coal-water or coal-oil mixture combustion and in diesel engines as a noncorrosive clean fuel. The advanced bench scab process developed may be improved by scaling up the present work and undertaking further work on process economics and studies on the major engineering problems involved.