1. Ntxiv cov kua paraffin rau saum npoo ntawm daim ntawv tais, muab tso rau hauv cov khoom, tos ib pliag, thiab mam li nqus ib txheej ntawm cov quav ciab zaj duab xis rau saum npoo ntawm cov khoom, kom cov dej noo - pov thawj muaj nuj nqi.
2. Siv cov khoom siv roj pleev xim rau saum npoo ntawm daim ntawv tais.
3. Nyob rau hauv cov txheej txheem ntawm kev tsim cov ntawv tais, ua kom cov pob zeb hmoov ntau ntxiv, kom cov tawv tawv ntawm cov tais ntawv tuaj yeem nce ntxiv, txawm tias nws ntub, siv nws txuas ntxiv.
