After coming into contact with yellow-banded millipede defensive secretion, rinse the affected area immediately and thoroughly with clean, warm water. Aleak soap may also be used to help remove the irritating substance. Afterward, avoid touching or scratching the irritated area as it may lead to secondary infection. Remember, it is always best to seek advice from a healthcare professional when dealing with insect encounters, especially if you are unsure of the type of creature or the person's medical history.