‘Ali reported God's messenger as saying, “If anyone leaves a spot on a hair which has been sexually defiled without washing it, such and such an amount of hell will have to be suffered for it.” ‘Ali said, “On that account I cut my hair; on that account I cut my hair,”* saying it three times.
*Lit. "I treated my hair as an enemy."
Abu Dawud, Ahmad and Darimi transmitted it, but Ahmad and Darimi did not repeat, “On that account I cut my hair.”
She also said that the Prophet used to wash his head with marshmallow when sexually defiled, contenting himself with that and not pouring water over it.
وَعَنْ أَبِي هُرَيْرَةَ قَالَ: قَالَ رَسُولُ اللَّهِ صلى الله عَلَيْهِ وَسلم: «تَحت كل شَعْرَة جَنَابَةٌ فَاغْسِلُوا الشَّعْرَ وَأَنْقُوا الْبَشْرَةَ» . رَوَاهُ أَبُو دَاوُدَ وَالتِّرْمِذِيُّ وَابْنُ مَاجَهْ وَقَالَ التِّرْمِذِيُّ: هَذَا حَدِيثٌ غَرِيبٌ وَالْحَارِثُ بْنُ وَجِيهٍ الرَّاوِي وَهُوَ شيخ لَيْسَ بذلك
Abu Huraira reported God's messenger as saying, “There is sexual defilement under every hair, so wash the hair and cleanse the skin.”
Abu Dawud, Tirmidhi and Ibn Majah transmitted it, and Tirmidhi said, “This is a gharib tradition, and al-Harith b. Wajih who is the transmitter is a shaikh one cannot trust.”