Soak the vegetables with catkins in clear water to remove most of the catkins, and take them out after soaking for 5 to 6 minutes.

After taking out, a small amount of catkins are still attached to the vegetables. Wash the vegetables under clean water, so that all the catkins are cleaned up.

You can use a watering can to sprinkle some water indoors and then clean it. You can use a vacuum cleaner if possible. The best way is to install a screen window to avoid endless troubles.