This article presents the results of experimental studies on the influence of different конструктив parameters of peg-and-plank drums on the process of separating fine impurities from raw cotton. While maintaining the overall drum diameter at 400 mm, the internal shell diameters (300, 270, 240, and 210 mm) and peg lengths (50, 65, 80, and 95 mm) were varied. The experiments were conducted at processing capacities of 3, 5, and 7 tons per hour using grade I and grade III cotton. The results demonstrated that increasing the peg length and reducing the internal shell diameter improved the degree of cotton loosening and reduced mechanical damage to the seeds. The optimal performance was observed at an internal diameter of 240 mm and a peg length of 80 mm, ensuring high cleaning efficiency with minimal seed damage. The proposed конструктив improvements contribute to enhancing the technological efficiency of cotton cleaning machines and improving the quality of cotton processing.