Cov khoom siv roj hmab yog ib qho ntawm cov kev lag luam tseem ceeb ntawm kev lag luam hauv lub tebchaws. Lawv tsis tsuas yog muab cov khoom siv roj hmab rau lub neej txhua hnub tab sis kuj yog rau cov khoom lag luam xws li cov khoom siv hluav taws xob, cov cuab yeej kho vajtse, rooj tog zaum, khoom siv kho mob, thiab kev lag luam teeb. Roj hmab lev yog qhov zoo nkauj, siv tau yooj yim, thiab muaj cov haujlwm xws li tiv thaiv - plam, tiv thaiv - kev sib tsoo, kev poob siab, qhov kub thiab txias, thiab txo suab nrov.
Nrog rau kev txhim kho ntawm tib neeg kev ua neej nyob, cov mats roj hmab tam sim no tau siv dav hauv cov khoom siv hluav taws xob, khoom siv hluav taws xob, rooj tog zaum, cov cuab yeej kho vajtse, cov khoom siv ncaws pob, cov khoom siv hlau, cov twj paj nruag, thiab cov khoom lag luam teeb, thiab lwm yam.
Lawv yuav tsum tau muab khaws cia rau hauv qhov chaw qhuav, zoo - qhov chaw tso cua sov, kom deb ntawm qhov chaw sov, yam tsawg 20cm saum toj no hauv av thiab phab ntsa, thiab muab ntim rau hauv hnab yas kom tsis txhob raug cov khoom corrosive xws li acids, alkalis, thiab roj. Tsis txhob cia lawv tawm sab nraum zoov lossis hauv tshav ntuj ncaj qha.
