Roj hmab los nag khau looj plab hlaub tuaj yeem oxidize, tshav kub thiab kub, thiab lwm yam, uas tuaj yeem ua rau cov khoom siv roj hmab nrawm nrawm thiab ua rau lawv nyuaj.Tig muag muag. Yog li ntawd, cov kaus mom los nag yuav tsum tsis txhob raug lub hnub ntev, thiab yuav tsum tsis txhob raug tshav ntuj thiab hluav taws. Tsis tas li ntawd tsis txhob sib cuag nrog lub tes tsho coal, roj av, thiab lwm yam, vim hais tias cov tshuaj kuab tshuaj no yuav yaj cov roj hmab, ua rau cov nplaum nplaum. Thaum hnav, tsis txhob kov cov khoom tawv xws li iav tawg, hlau hlau, ntsia hlau, thiab lwm yam. Tom qab ntawd, koj siv tsis tau ntxiv.