Chlorine, which, in general, can be easily washed out from coals or biomass, is not mentioned up to now. Table 3 shows an increase in chlorine content for the demineralized samples up to several times compared to the original one (except for wheat straw). This is a result of the demineralization procedure. Washing of the samples with diluted hydrochloric acid, as mentioned before, leads to an entry of chlorine to the sample. The subsequent flushing with distilled water for several times was elaborate and it was not possible to remove all the chlorine from the samples. Hence, no suggestion can be made about the chlorine reduction caused by the demineralization process.