2. Wash and soak gai choi very well to remove sand and dirt. Boil a pot of water, wait until it’s boiling. Then, add washed gai choi and make sure all the leaves are soaked in boiling water. Don’t need to completely cook. Just soak in boiling water for a few seconds. The purpose of this is to kill bacterias and sterilize the vegetables because I washed the vegetables and did not put them under the sun.