Sahih al-Bukhari 312
Sahih al-Bukhari · Book 6: Menstrual Periods · Can a woman offer her Salat (prayers) in the clothes in which she has her menses?
Narrated `Aisha:
حَدَّثَنَا أَبُو نُعَيْمٍ ، قَالَ حَدَّثَنَا إِبْرَاهِيمُ بْنُ نَافِعٍ ، عَنِ ابْنِ أَبِي نَجِيحٍ ، عَنْ مُجَاهِدٍ ، قَالَ قَالَتْ عَائِشَةُ مَا كَانَ لإِحْدَانَا إِلاَّ ثَوْبٌ وَاحِدٌ تَحِيضُ فِيهِ، فَإِذَا أَصَابَهُ شَىْءٌ مِنْ دَمٍ، قَالَتْ بِرِيقِهَا فَقَصَعَتْهُ بِظُفْرِهَا.
None of us had more than a single garment and we used to have our menses while wearing it. Whenever it got soiled with blood of menses we used to apply saliva to the blood spot and rub off the blood with our nails.