Hanafi
The sources give no view for it here.
حكم الأسآر
ما حكم الأسآر من حيث الطهارة؟
Each school’s answer
In our wordsHanafi
Not stated in the sources
Maliki
الأسآر طاهرة
طاهرةShafi'i
Not stated in the sources
Hanbali
Not stated in the sources
The texts
الْحُكْمُ التَّكْلِيفِيُّ: ٢ - اخْتَلَفَ الْفُقَهَاءُ فِي أَحْكَامِ الأَْسْآرِ عَلَى اتِّجَاهَيْنِ: أَحَدُهَا: يَذْهَبُ إِلَى طَهَارَةِ الأَْسْآرِ، وَهُوَ مَذْهَبُ الْمَالِكِيَّةِ.
«الموسوعة الفقهية الكويتية» (Kuwait) entry «سؤر» vol. 24 p. 100
From the schools’ own books
Maliki
طاهرةIts place in the school’s books is not linked yet.
Shafi'i
The sources give no view for it here.
Hanbali
The sources give no view for it here.
What is «in our words» is our standard wording; the books’ texts stay as they are.