1. Thaum tshem cov stains ntawm lub qhov rooj ntoo, siv ib daim ntaub mos mos los so, vim qhov nyuaj tuaj yeem khawb tau yooj yim. Thaum cov stains hnyav dhau lawm, cov tshuaj txhuam hniav tsis zoo lossis cov rooj tog tshwj xeeb tuaj yeem siv los tshem tawm cov stains ua ntej qhuav so. Tsis txhob yaug nrog dej.
2. Ceev faj tsis txhob tso cov ntaub so hauv qhov nruab nrab reagents los yog dej rau ntawm qhov chaw ntawm lub qhov rooj ntoo ntev ntev, vim nws yuav ua rau lub ntsej muag puas tsuaj thiab ua rau cov xim tsis zoo los yog tev ntawm cov khoom tiav.
3. Ceev faj tsis txhob txhuam ntau dhau ntawm cov npoo thiab cov ces kaum ntawm cov qhov rooj ntoo, txwv tsis pub nws yuav ua rau cov xim tev tawm.
4. Thov nco ntsoov tias cov qhov rooj ntoo yuav tsum tsis txhob cuam tshuam los ntawm cov tshuaj muaj zog acid lossis alkali, vim qhov no tuaj yeem ua rau cov xim tev lossis txawm ntoo lwj.
5. Lub pob khawm xauv yog ib qho khoom siv txav tau uas yuav tsum tau nruj tam sim ntawd yog tias nws xoob. Kev ceev faj yuav tsum tau them sai sai yog tias muaj suab nrov ntawm lub pob khawm. Yog tias lub ntsuas phoo tsis hloov pauv thaum qhib, qhov tsim nyog ntawm cov xaum hmoov hmoov tuaj yeem muab ntxiv rau hauv lub qhov tseem ceeb, thiab cov roj yuav tsum tsis txhob txhaj tshuaj tsis tu ncua.
6. Vim tias qhov ziab ziab thiab qhov o ntawm cov ntoo, me ntsis tawg los yog shrinkage nyob rau hauv qhov kub thiab av noo qhov sib txawv yog ib txwm tshwm sim, uas yuav ploj mus nrog lub caij hloov.
7. Txhawm rau tswj cov xim ci ntawm cov qhov rooj ntoo, lawv yuav tsum tsis tu ncua waxed rau kev tu.