In this study, sequential leaching (60 degrees C, 5 min) and wet torrefaction (200 degrees C, 5 min) of biomass were carried out to improve the fuel properties of waste biomass, made up of empty fruit bunches (EFB), rice straws (RS), or sugarcane bagasses (SB). Most of the hemicellulose was removed during wet torrefaction. The ash removal efficiency by sequential leaching and wet torrefaction differed depending on the biomass. After leaching and wet torrefaction, the ash removal efficiency of the EFB was the highest (67.99%). Most of the potassium and chloride in the biomass were removed. In particular, the removal efficiencies for the EFB were the highest (98.62% and 99.27%, respectively). The heating values increased by 4.42% in the EFB, 4.68% in the RS, and 5.30% in the SB. Pellet production was successfully carried out with the leaching and wet-torrefied biomass (EFB). The hydrophobicity of the pellets was considerably higher than that of the raw material.