Sahih al-Bukhari 230
Sahih al-Bukhari · Book 4: Ablutions (Wudu') · The washing out of semen with water and rubbing it off (when it is dry) and the washing out of what comes out of women (i.e., discharge)
Narrated Sulaiman bin Yasar:
حَدَّثَنَا قُتَيْبَةُ ، قَالَ حَدَّثَنَا يَزِيدُ ، قَالَ حَدَّثَنَا عَمْرٌو ، عَنْ سُلَيْمَانَ ، قَالَ سَمِعْتُ عَائِشَةَ ، ح وَحَدَّثَنَا مُسَدَّدٌ ، قَالَ حَدَّثَنَا عَبْدُ الْوَاحِدِ ، قَالَ حَدَّثَنَا عَمْرُو بْنُ مَيْمُونٍ ، عَنْ سُلَيْمَانَ بْنِ يَسَارٍ ، قَالَ سَأَلْتُ عَائِشَةَ عَنِ الْمَنِيِّ، يُصِيبُ الثَّوْبَ فَقَالَتْ كُنْتُ أَغْسِلُهُ مِنْ ثَوْبِ رَسُولِ اللَّهِ صلى الله عليه وسلم، فَيَخْرُجُ إِلَى الصَّلاَةِ وَأَثَرُ الْغَسْلِ فِي ثَوْبِهِ بُقَعُ الْمَاءِ.
I asked `Aisha about the clothes soiled with semen. She replied, "I used to wash it off the clothes of Allah's Messenger (ﷺ) and he would go for the prayer while water spots were still visible. "