The discovery of new methods to control porosity and microarchitecture may lead to the refinement of carbon materials from lignocellulose as advanced functional materials. However, the high ash content on the surface of lignocellulosic biomass reduces the surface area and adsorption properties of the activated carbon. This study presents a novel approach, using a deashing post-treatment as the pore generator, to increase the quality of the activated carbon. The micropore capacity was improved by deashing post-treatment with distilled water, where 80% of the total pore ratio of the activated carbon was occupied with micropores. Ultrasonic treatment was able to penetrate deeper into the structure of coconut shell activated carbon, creating cavities and pores, thus increasing the surface area. Understanding the effects of these new controlling methods on pore refinement can elucidate the microporous fabrication of other activated carbons from high ash-content lignocellulosic biomass.