Feem ntau, cov ntaub ntub dej yog tsim nyob rau hauv ob peb kauj ruam. Cov txheej txheem tsim khoom pib nrog kev npaj cov khoom siv raw xws li cov pulp, tshuaj, thiab tshuaj tsw qab, feem ntau ua kua. Tom qab ntawd cov khoom xyaw yog sib tov ua ke los tsim ib homogeneous sib tov. Daim ntawv ntub dej ces muab tso rau hauv lub tshuab thiab txiav rau hauv qhov xav tau ntub so loj. Nyob rau lub sijhawm no, cov khoom xyaw ntxiv xws li moisturizers, tshuaj tua kab mob, lossis tshuaj tsw qab tuaj yeem ntxiv rau cov ntaub ntub dej. Thaum kawg, cov ntaub so ntub dej tau ntim, sau npe, thiab kaw kom ntseeg tau tias cov khoom siv tu cev, tamper-proof.
