وَإِنْ كُنْتُمْ جُنُبًا فَاطَّهَّرُوا
Translation: If you are in a state of major impurity, purify yourselves. (Quran 5:6)
The Hanafi inference is that accessible internal areas such as the mouth and nose fall under full purification, unlike the outward face specified in the wudu command.