1. Do not cut open the pig lungs when you first buy them. This is a mistake many people make. You should first fill the inside of the pig lungs with water to allow the pig lungs to swell.

2. After inflating, press the pig's lungs hard with your hands to squeeze out the water. Then fill and squeeze the water according to the previous method, which can effectively discharge the dirt inside the pig's lungs until the boiled color turns white.

3. At this time, cut the pig lungs into small pieces and wash them with clean water. Many people directly cut the pig lungs into pieces and wash them when they buy them back. In this way, the pig lungs cannot be cleaned.

4. Take a clean pot and add enough water, pour in the cut pig lungs and cook over high heat. This will remove a lot of the blood in the pig lungs.

5. After boiling, take out the pig lungs, then add a certain amount of water and boil them again to clean them more cleanly.

6. Finally, remove the cooked pig lungs, and then rinse them with cold water. This way, you can use the principle of thermal expansion and contraction to clean the foam inside the pig lungs. Just rinse them twice.