Yahya related to me from Malik from AIqama ibn Abi AIqama that his mother, the mawla of A'isha, umm al-muminin, said, "Women used to send little boxes to A'isha, umm al-muminin, with a piece of cotton cloth in each one on which was yellowness from menstrual blood, asking her about the prayer. She said to them, 'Do not be hasty until you see a white discharge." By that she meant purity from menses.  

أَنَّهَا قَالَتْ كَانَ النِّسَاءُ يَبْعَثْنَ إِلَى عَائِشَةَ أُمِّ الْمُؤْمِنِينَ بِالدِّرَجَةِ فِيهَا الْكُرْسُفُ فِيهِ الصُّفْرَةُ مِنْ دَمِ الْحَيْضَةِ يَسْأَلْنَهَا عَنِ الصَّلاَةِ فَتَقُولُ لَهُنَّ لاَ تَعْجَلْنَ حَتَّى تَرَيْنَ الْقَصَّةَ الْبَيْضَاءَ تُرِيدُ بِذَلِكَ الطُّهْرَ مِنَ الْحَيْضَةِ  

Yahya related to me from Malik from Abdullah ibn Abi Bakr from his paternal aunt from the daughter of Zayd ibn Thabit that she had heard that women used to ask for lamps in the middle of the night to check their purity. She would criticise them for this saying, "Women never used to do this," i.e. in the time of the companions. Malik was asked whether a woman whose period had finished could do tayammum to purify herself if she could not find waterand he said, "Yes, because she is like some one in a state of major ritual impurity, who, if he cannot find water, does tayammum."  

أَنَّ نِسَاءً كُنَّ يَدْعُونَ بِالْمَصَابِيحِ مِنْ جَوْفِ اللَّيْلِ يَنْظُرْنَ إِلَى الطُّهْرِ فَكَانَتْ تَعِيبُ ذَلِكَ عَلَيْهِنَّ وَتَقُولُ مَا كَانَ النِّسَاءُ يَصْنَعْنَ هَذَا وَسُئِلَ مَالِكٌ عَنِ الْحَائِضِ تَطْهُرُ فَلاَ تَجِدُ مَاءً هَلْ تَتَيَمَّمُ قَالَ نَعَمْ لِتَتَيَمَّمْ فَإِنَّ مِثْلَهَا مِثْلُ الْجُنُبِ إِذَا لَمْ يَجِدْ مَاءً تَيَمَّمَ