She should wash it; in case mark is not removed she should change it by applying some yellow color. I had three menstruations together while I lives with the Messenger of Allah ﷺ, but I did not wash my clothes.  

حَدَّثَنِي أَبِي حَدَّثَتْنِي أُمُّ الْحَسَنِ يَعْنِي جَدَّةَ أَبِي بَكْرٍ الْعَدَوِيِّ عَنْ مُعَاذَةَ قَالَتْ سَأَلْتُ عَائِشَةَ ؓ عَنِ الْحَائِضِ يُصِيبُ ثَوْبَهَا الدَّمُ قَالَتْ تَغْسِلُهُ فَإِنْ لَمْ يَذْهَبْ أَثَرُهُ فَلْتُغَيِّرْهُ بِشَىْءٍ مِنَ صُفْرَةٍ قَالَتْ وَلَقَدْ كُنْتُ أَحِيضُ عِنْدَ رَسُولِ اللَّهِ ﷺ ثَلاَثَ حِيَضٍ جَمِيعًا لاَ أَغْسِلُ لِي ثَوْبًا  

Each of us (wives of the Prophet) had only one clothe in which she would menstruate. Whenever it was smeared with blood, she would moisten it with her saliva and scratch it with saliva.  

عَائِشَةُ مَا كَانَ لإِحْدَانَا إِلاَّ ثَوْبٌ وَاحِدٌ تَحِيضُ فِيهِ فَإِنْ أَصَابَهُ شَىْءٌ مِنْ دَمٍ بَلَّتْهُ بِرِيقِهَا ثُمَّ قَصَعَتْهُ بِرِيقِهَا  

Bakkar ibn Yahya said that his grandmother narrated to him: I entered upon Umm Salamah. A woman from the Quraysh asked her about praying with the clothes which a woman wore while she menstruated. Umm Salamah said: We would menstruate in the lifetime of the Messenger of Allah ﷺ. Then each one of us refrained (from prayer) during menstrual period. When she was purified, she would look at the clothe in which she menstruated. If it were smeared with blood, we would wash it and pray with it; if there were nothing in it, we would leave it and that would not prevent us from praying with it (the same clothe). As regards the woman who had plaited hair - sometimes each of us had plaited hair - when she washed, she would not undo the hair. She would instead pour three handfuls of water upon her head. When she felt moisture in the roots of her hair, she would rub them. Then she would pour water upon her whole body.  

دَخَلْتُ عَلَى أُمِّ سَلَمَةَ فَسَأَلَتْهَا امْرَأَةٌ مِنْ قُرَيْشٍ عَنِ الصَّلاَةِ فِي ثَوْبِ الْحَائِضِ فَقَالَتْ أُمُّ سَلَمَةَ قَدْ كَانَ يُصِيبُنَا الْحَيْضُ عَلَى عَهْدِ رَسُولِ اللَّهِ ﷺ فَتَلْبَثُ إِحْدَانَا أَيَّامَ حَيْضِهَا ثُمَّ تَطْهُرُ فَتَنْظُرُ الثَّوْبَ الَّذِي كَانَتْ تَقْلِبُ فِيهِ فَإِنْ أَصَابَهُ دَمٌ غَسَلْنَاهُ وَصَلَّيْنَا فِيهِ وَإِنْ لَمْ يَكُنْ أَصَابَهُ شَىْءٌ تَرَكْنَاهُ وَلَمْ يَمْنَعْنَا ذَلِكَ مِنْ أَنْ نُصَلِّيَ فِيهِ وَأَمَّا الْمُمْتَشِطَةُ فَكَانَتْ إِحْدَانَا تَكُونُ مُمْتَشِطَةً فَإِذَا اغْتَسَلَتْ لَمْ تَنْقُضْ ذَلِكَ وَلَكِنَّهَا تَحْفِنُ عَلَى رَأْسِهَا ثَلاَثَ حَفَنَاتٍ فَإِذَا رَأَتِ الْبَلَلَ فِي أُصُولِ الشَّعْرِ دَلَكَتْهُ ثُمَّ أَفَاضَتْ عَلَى سَائِرِ جَسَدِهَا  

I heard a woman asking the Messenger of Allah ﷺ: What should any of us to with her clothe (in which she menstruated) when she becomes purified ? Can she pray in that (clothe) ? He said: She should see; if she finds blood in it, she should scratch it with some water and (in case of doubt) sprinkle upon it (some water) and pray so long as she does not find (any blood).  

سَمِعْتُ امْرَأَةً تَسْأَلُ رَسُولَ اللَّهِ ﷺ كَيْفَ تَصْنَعُ إِحْدَانَا بِثَوْبِهَا إِذَا رَأَتِ الطُّهْرَ أَتُصَلِّي فِيهِ قَالَ تَنْظُرُ فَإِنْ رَأَتْ فِيهِ دَمًا فَلْتَقْرُصْهُ بِشَىْءٍ مِنْ مَاءٍ وَلْتَنْضَحْ مَا لَمْ تَرَ وَلْتُصَلِّ فِيهِ  

A woman asked the Messenger of Allah ﷺ: Messenger of Allah, what do you think if the clothe of any of us smeared with the blood of menstruation; what should she do ? He said: If (the clothe of) any of you is smeared with blood of menstruation, she should scratch it; then she should sprinkle water upon it and then she may pray.  

أَنَّهَا قَالَتْ سَأَلَتِ امْرَأَةٌ رَسُولَ اللَّهِ ﷺ فَقَالَتْ يَا رَسُولَ اللَّهِ أَرَأَيْتَ إِحْدَانَا إِذَا أَصَابَ ثَوْبَهَا الدَّمُ مِنَ الْحَيْضَةِ كَيْفَ تَصْنَعُ قَالَ إِذَا أَصَابَ إِحْدَاكُنَّ الدَّمُ مِنَ الْحَيْضِ فَلْتَقْرِصْهُ ثُمَّ لْتَنْضَحْهُ بِالْمَاءِ ثُمَّ لْتُصَلِّي  

Rub it off (with a stone), and then scratch it (with finger) by pouring water, then sprinkle water upon it.  

حُتِّيهِ ثُمَّ اقْرُصِيهِ بِالْمَاءِ ثُمَّ انْضَحِيهِ  

I asked the Prophet ﷺ about the blood of menstruation on the clothe. He said: Erase it off with a piece of wood and then wash it away with water and the leaves of the lote-tree.  

سَمِعْتُ أُمَّ قَيْسٍ بِنْتَ مِحْصَنٍ تَقُولُ سَأَلْتُ النَّبِيَّ ﷺ عَنْ دَمِ الْحَيْضِ يَكُونُ فِي الثَّوْبِ قَالَ حُكِّيهِ بِضِلْعٍ وَاغْسِلِيهِ بِمَاءٍ وَسِدْرٍ  

One of us would have a shirt in which she would menstruate and in it she became sexually defiled. Then if she ever saw any drop of blood in it, she would rub it off by applying her saliva.  

قَدْ كَانَ يَكُونُ لإِحْدَانَا الدِّرْعُ فِيهِ تَحِيضُ وَفِيهِ تُصِيبُهَا الْجَنَابَةُ ثُمَّ تَرَى فِيهِ قَطْرَةً مِنْ دَمٍ فَتَقْصَعُهُ بِرِيقِهَا  

Messenger of Allah, I have only one clothe and I menstruate in it, how should I do ? He said: When you are purified, wash it and pray in it. She asked: If the blood is not removed, (then what) ? He said: It is enough for you to wash the blood, its mark will not do any harm to you.  

أَنَّ خَوْلَةَ بِنْتَ يَسَارٍ أَتَتِ النَّبِيَّ ﷺ فَقَالَتْ يَا رَسُولَ اللَّهِ إِنَّهُ لَيْسَ لِي إِلاَّ ثَوْبٌ وَاحِدٌ وَأَنَا أَحِيضُ فِيهِ فَكَيْفَ أَصْنَعُ قَالَ إِذَا طَهُرْتِ فَاغْسِلِيهِ ثُمَّ صَلِّي فِيهِ فَقَالَتْ فَإِنْ لَمْ يَخْرُجِ الدَّمُ قَالَ يَكْفِيكِ غَسْلُ الدَّمِ وَلاَ يَضُرُّكِ أَثَرُهُ