[Machine] The Messenger of Allah ﷺ was asked about semen that gets on clothing, so he said: "It is similar to saliva or mucus. It is sufficient for you to wipe it with a cloth or a tissue." This was narrated by Wakī' from Ibn Abī Laylā, suspended on the authority of Ibn 'Abbās, and it is considered authentic.
سُئِلَ رَسُولُ اللهِ ﷺ عَنِ الْمَنِيِّ يُصِيبُ الثَّوْبَ فَقَالَ إِنَّمَا هُوَ بِمَنْزِلَةِ الْبُصَاقِ أَوِ الْمُخَاطِ إِنَّمَا كَانَ يَكْفِيكَ أَنْ تَمْسَحَهُ بِخِرْقَةٍ أَوْ إِذْخِرٍ وَرَوَاهُ وَكِيعٌ عَنِ ابْنِ أَبِي لَيْلَى مَوْقُوفًا عَلَى ابْنِ عَبَّاسٍ وَهُوَ الصَّحِيحُ