Hadithcore
Sahih Muslim, 289b
sahih

Abu Kuraib, Ibn al-Mubarak, Ibn Abu Za'ida all of them narrated from Amr b. Maimun with the same chain of transmitters. Ibn Abu Za'ida narrated as was transmitted from Ibn Bishr that the Messenger of Allah (ﷺ) washed semen, and in the hadith transmitted on the authority of Ibn Mabarak and Abdul Wahid the words are:

" She (A'isha) reported: I used to wash it from the garment of the Messenger of Allah (ﷺ)."

وَحَدَّثَنَا أَبُو كَامِلٍ الْجَحْدَرِيُّ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، - يَعْنِي ابْنَ زِيَادٍ ح وَحَدَّثَنَا أَبُو كُرَيْبٍ، أَخْبَرَنَا ابْنُ الْمُبَارَكِ، وَابْنُ أَبِي زَائِدَةَ، كُلُّهُمْ عَنْ عَمْرِو بْنِ مَيْمُونٍ، بِهَذَا الإِسْنَادِ أَمَّا ابْنُ أَبِي زَائِدَةَ فَحَدِيثُهُ كَمَا قَالَ ابْنُ بِشْرٍ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يَغْسِلُ الْمَنِيَّ وَأَمَّا ابْنُ الْمُبَارَكِ وَعَبْدُ الْوَاحِدِ فَفِي حَدِيثِهِمَا قَالَتْ كُنْتُ أَغْسِلُهُ مِنْ ثَوْبِ رَسُولِ اللَّهِ صلى الله عليه وسلم ‏.‏

References2 variants
In-Book Reference
Book 2, Hadith 139
USC-MSA web (English) reference
Book 2, Hadith 571 (deprecated numbering scheme)