How can one distinguish between the white discharge (al-qassah al-bayda') and natural secretions? And is it possible for the white discharge (al-qassah al-bayda') to recur?

The "white discharge" (al-qassah al-bayda') is a sign of a woman's purification from menstruation. Scholars have differed on its interpretation, holding two views: The first is that it is a white fluid that appears at the end of menstruation. The second is that a woman inserts a piece of cotton into her private parts, and it comes out pure white. So, if a woman sees the white fluid, or her private parts become dry such that if she were to insert a piece of cotton it would come out white, then she has become pure.