Kev Kho Txhua Hnub Ntawm Qhov Rooj zawv zawg

1. Ua kom huv si.
2. Ceev faj ntawm cov khoom hnyav ntaus tus khiav.
3. Ntxuav nrog cov tshuaj tsis muaj corrosive.
4.Yog hais tias daim iav los yog board nto puas lawm, cov kws tshaj lij tuaj yeem thov kom hloov nws.
5.Rau qhov laj thawj kev nyab xeeb, nws yog ib qho tseem ceeb uas yuav tsum nquag xyuas seb cov khoom tiv thaiv dhia puas ua haujlwm.
6. Thaum pom tias lub qhov rooj lub cev tsis nruj nreem txuas rau ntawm phab ntsa, thov nug tus kws tshaj lij los kho cov ntsia hlau hauv qab kom ua tiav kev sib txuas ntawm lub qhov rooj thiab phab ntsa.