Soaking in salt water is a commonly used method of cleaning ingredients, which can help remove impurities and pesticide residues from the surface of broccoli. Soaking broccoli in salt water for a period of time and then rinsing with water can effectively clean broccoli. Detergent water is a specialized cleaning agent used for cleaning ingredients and has the ability to remove pesticide residues and impurities. Following the instructions for cleaning with dishwashing liquid will further ensure that the broccoli is hygienic and clean. Blanching is a pre-cooking treatment that removes odors, kills bacteria, and improves the color of ingredients by cooking them briefly in boiling water. When blanching broccoli, adding a small amount of edible alkali (e.g. baking soda) can bring back the green color of yellowed broccoli, this is because edible alkali is able to change the acid and alkaline nature of the ingredient, and make its color change back to green.