Raws li cov khoom siv kho dej, cov yeeb nkab inclined feem ntau yog siv rau kev kho dej phwj, xws li cov kav dej phwj tshuaj, cov dej phwj hauv tsev, cov dej phwj hauv chaw tsim tshuaj, cov dej phwj hauv cov ntawv zeb, thiab lwm yam. kuj tseem siv tau rau kev lim dej thiab xa cov xuab zeb tshem tawm ntxiv rau kev kho dej phwj tuaj.