1. Ka whakamahia hei whakarewa kore mura me te reagent tātari
2. Ko te whakarewa pai, ka whakamahia hei kaihoko maimoatanga mata whakarewa, hei horoi horoi i mua i te whakakikorua me te peita, te whakakore whakarewa me te tangohanga o te ngako, te hinu me te paraffin.
3. Ka whakamahia i roto i te whakahiato waro me te hanga pesticide.
4. Mo te horoi matū, te whakakore i te ahumahi, nga rauemi mata matū
5. Ka taea te whakamahi hei whakarewa kore mura, te whakatau uara iodine me te whakahiato waro.