Ma’yaqib says: “I asked the Prophet about dusting [away] the pebbles during the salah, and the Prophet said: ‘Do not dust [away] the pebbles while you are praying, but if you must do it, then do it only once in order to level the pebbles.'” This is related by the group.
Abu Zharr reports that the Prophet said: “When one of you stands for the salah, mercy is facing him. Therefore, he should not wipe away the pebbles.” This is related by Ahmad, at-Tirmizhi, Abu Dawud, an-Nasa’i, and Ibn Majah.
Umm Salamah reports that there was a boy called Yassar who would puff out some air during the salah. The Messenger of Allah said to him: “May Allah fill your face with dust!” This is related by Ahmad with a good chain.