They (the Companions of the Prophet) wiped with pure earth (their hands and face) to offer the dawn prayer in the company of the Messenger of Allah ﷺ. They struck the ground with their palms and wiped their faces once. Then they repeated and struck the ground with their palms once again and wiped their arms completely up to the shoulders and up to the armpits with the inner side of their hands.  

أَنَّهُ كَانَ يُحَدِّثُ أَنَّهُمْ تَمَسَّحُوا وَهُمْ مَعَ رَسُولِ اللَّهِ ﷺ بِالصَّعِيدِ لِصَلاَةِ الْفَجْرِ فَضَرَبُوا بِأَكُفِّهِمُ الصَّعِيدَ ثُمَّ مَسَحُوا وُجُوهَهُمْ مَسْحَةً وَاحِدَةً ثُمَّ عَادُوا فَضَرَبُوا بِأَكُفِّهِمُ الصَّعِيدَ مَرَّةً أُخْرَى فَمَسَحُوا بِأَيْدِيهِمْ كُلِّهَا إِلَى الْمَنَاكِبِ وَالآبَاطِ مِنْ بُطُونِ أَيْدِيهِمْ