Nws yog tsim rau sau cov khoom noj nqaij, hnyuv ntxwm, cov khoom noj siv mis, cov khoom ntses, cov khoom noj tam sim, cov zaub mov siav, cov zaub mov tsiaj thiab lwm yam ntaub ntawv.Tom qab cov cuab yeej knotting tau teeb tsa, cov khoom tuaj yeem suav tau los ntawm gram.Lub tshuab no yog tsim rau cov protein casing, ntuj casing, cellulose casing, yas casing thiab hais txog.Thiab tuaj yeem siv nrog txiav tshuab, kev kub ceev knotting tshuab, ntim tshuab.