1. Xaiv lub lauj kaub hnyav (tshwj xeeb hauv qab). Lub lauj kaub hnyav yog ruaj khov, ruaj khov, thiab tsis tshua muaj kub kub.
2. Lub hauv qab ntawm lub lauj kaub yuav tsum tsis txhob me heev. Thaum siv lub qhov cub roj lossis lwm cov nplaim taws qhib, lub hauv qab me me yuav tsis npog cov nplaim taws, ua rau nws kis tau thiab muaj peev xwm hlawv lwm qhov chaw. Qhov no yog ob qho tib si tsis yooj yim thiab tsis nyab xeeb.
3. Cov khoom siv tseem ceeb. Lub tshav kub- ua cov hlau tuav yuav kub heev thaum siv, yooj yim hlawv koj txhais tes thiab yuav ua rau muaj xwm txheej kub ntxhov. Cov khoom siv yas zoo tib yam yog qhov ua rau deformation, tsim cov ntxhiab tsw, thiab tso cov khoom tsis zoo. Nws raug pom zoo kom yuav cov khoom lag luam los ntawm cov kws tshaj lij, vim tias cov no feem ntau muaj cov rwb thaiv tsev kub zoo dua thiab nplaim taws- qauv tsim.
4. Lub hau tsim yog qhov tseem ceeb. Lub hau yuav tsum muaj lub qhov cua hloov tau los tiv thaiv kev nchuav thiab yooj yim rau qhov chaw thiab tuav, tsis txhob hlawv thiab drips.