The invention refers to a methodology for the removal of inorganic components such as potassium, sodium, chlorine, sulfur, phosphorus and heavy metals from biomass of different origins, such as from agricultural, forest or urban origin and any mixture therefrom, from low quality coals such as peat, lignite or sub-bituminous and/or bituminous coals, from urban and/or industrial origin residues and wastes, which are possible to include as much organic—>5 wt %—as inorganic—