essalemoe 3laikoum shaykh, Can we do mash on thin socks and how do we do mash on socks? Is the kayfiyyah from beginning of toes to the height of ankles and are the fingers of our hand spread or tight while doing this? May Allah reward you for your efforts, amin. salem

All perfect praise be to Allaah, the Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

If what you mean by thin socks those through which the skin can be seen, then wiping over them is not allowed. Al-Buhooti said in Kash-shaaf Al-Qinaa': “Whatever shows the skin due to its transparency, then it is not allowed to wipe over it.”

Some jurists held the opinion that it is permissible to wipe over them, as was the chosen opinion of Ibn ‘Uthaymeen who said: “It is permissible to wipe over thin socks, even if the skin can be seen through them, and even if water can pass through them to the foot. This is the correct opinion.” But there is no doubt that the first opinion is safer to keep one acquitted from liability.

However, if what you mean is that the socks are thin but the skin cannot be seen through them, then this type of socks can be wiped over if it is possible to walk in them without them falling off. Ibn Qudaamah said in Al-Mughni: “Wiping over the socks is only permissible with the two conditions which we also mentioned regarding the Khuff (leather sock): The first is that they are thick enough that nothing of the foot can be seen. The second is that it is possible to continually walk in them. This is the apparent meaning of what Al-Khiraqi said. Ahmad said, concerning wiping over two socks without soles (leather bottoms): If one can walk in them, and they are fixed upon his feet, then that is fine. Another time, he said: He can wipe over them if they remain fixed upon the heels.” Another time, he said: If he can walk in them without them falling off, then it is fine to wipe over it; because if they fall off, the area of foot which must be washed in ablution would be uncovered.” [End quote]

As for the method of wiping over the socks, then it is by placing the fingers of the right hand on the front of the right sock or Khuff and the fingers of the left hand on the left sock or Khuff, then one passes over them up to his shin above the ankles. He should spread out his fingers slightly. Al-Mardaawi  from the Hanbali School of jurisprudence, said in Al-Insaaf: “The way of wiping (over the Khuffs or socks) according to the Sunnah is to place one's hand with slightly spread out fingers on the ends of his toes, then passes over them up to one's shin one time for the right foot and the left foot. It is mentioned in At-Talkhees and Al-Bulghah (two Hanbali books) that it is Sunnah (a recommended act) to start with the right foot. But Al-Bayhaqi narrated that he (the Prophet, sallallaahu ‘alayhi wa sallam) wiped over both of his Khuffs in a single pass. The apparent meaning of this is that he did not wipe over one foot before the other. However one wipes is sufficient.” [End quote]

For more benefit, please refer to Fataawa 88478 and 82001 regarding the conditions and rulings of wiping over the Khuffs and socks.

Allaah Knows best.