I.
If a woman thinks that her menses has ended by seeing dryness or the white discharge, then her menses has ended and her fast and prayers after that are valid.
What appears to be the case is that what you mentioned of the emission of a clear fluid is a sign that your menses had ended, and it does not matter what comes out after that of yellowish or brownish discharge, or threads or drops of blood, because menses does not take the form of drops; rather it is blood that flows. Moreover, Umm `Atiyah (may Allah be pleased with her) said: We used not to regard yellowish or brownish discharge after the end of menses as being of any significance. Narrated by Abu Dawud, 307.
Shaykh Ibn `Uthaymin (may Allah have mercy on him) said: If A woman notices a few spots of blood during the day in Ramadan, and that continues with her throughout the month of Ramadan and she fasts, is her fast valid?
He replied: Yes, her fast is valid. As for these drops of blood, they are of no significance, because they come from veins. It was narrated from `Ali ibn Abi Talib (may Allah be pleased with him) that he said: These drops of blood that look like a nosebleed are not menses. This is what was narrated from him (may Allah be pleased with him).
End quote from 60 Su’al fil-Hayd, p. 6.
II.
Dryness is to be ascertained by inserting a piece of cotton and the like, and if it comes out clean, with no blood or yellowish or brownish discharge, then menses had ended. It is not sufficient to only wipe the outside of the private part.
Ibn Abi Shaybah said with his isnad in Al-Musannaf, 1/90:`Amrah bint `Abd ar-Rahman al-Madaniyyah (d. 98 AH) – one of the jurists of the Tabi`in – used to say to the women: If one of you inserts a piece of cotton and it comes out changed, then do not pray until you do not see anything.
Al-Bahuti (may Allah have mercy on him) said in Kashshaf al-Qina`, 1/204: The least sign that menses has ended is purity, meaning that the piece of cotton does not change in colour when inserted. End quote.
Shaykh Ibn `Uthaymin (may Allah have mercy on him) said in Ash-Sharh al-Mumti`, 1/498: The sign that menses has ended is known to women; it is a clear fluid that comes out when menses ceases. But some women do not see this fluid, and they remain until the next menses without seeing this fluid.
In that case, the sign that menses has ended is that if a woman inserts a piece of white cotton in the place of menses, and it comes out unchanged, that is the sign that her menses has ended. End quote.
Based on that, it is essential to insert the piece of cotton in the private part, according to the majority of scholars.
The outside of the private part is what appears when a woman squats to relieve herself, and the inside is whatever is beyond that, even a little bit.
This is based on what the scholars say: that the blood on the inside comes under the rulings on menses, even if it does not appear on the outside.
We have discussed the difference of scholarly opinion on this issue in the answer to question no. 222030.
We think that the view of the majority is the correct view.
But you said that some of this clear fluid came out of you, and this is a sign that your menses had ended, not merely wiping the private part with a tissue and seeing nothing on it.
Based on that, your fast of this day is valid.
And Allah knows best.
