Removal of foreign matter from cotton during the ginning process is a complex interaction of genetic traits, moisture differentials and machine performance parameters. Studies over a two-year period of 20 cotton cultivars grown in the Mid-south and processed identically at the gin indicated that large differences occur in the foreign matter removal characteristics (cleanability) of cotton cultivars. Cleaning efficiencies also differ for the types of gin cleaning machinery such as seed-cotton cleaners and lint cleaners.

Overall cleaning efficiencies adjusted each year to a common level of foreign matter for each cultivar ranged from a low of 71% for Coker 82-130 to 90% for Deltapine 50. Seed-cotton cleanability ranged from 48% for McNair 220 to 73% for Deltapine 90. Lint cleanability ranged from 29% for Coker 82-130 to 73% for Deltapine 90. Differences in cleaning levels occurred between years but the relative efficiencies remained similar for the cultivars. Results indicate that plant trichome density correlated highly with cotton cleanability. In general, Deltapine smoothleaf cultivars had the highest cleanability values.