The answer: I say, and may Allah grant success: Using the left hand for cleaning during ablution is a matter of etiquette; for Aisha (may Allah be pleased with her) said: "The hand of the Messenger of Allah (peace be upon him) was the right one for his purification and food, and his left hand was for his private parts and anything that was impure," as found in Sunan Abu Dawood 1/55, and in Sha'b al-Iman 5/77, and in the Sunan al-Kubra by al-Bayhaqi 1/113. Then, using the left hand is preferred for cleaning; this is because cleaning is the act of blowing the nose — which means expelling what is in the nostrils by breath, particularly the dried mucus — and the nostrils are where the devil resides; as he (peace be upon him) said: "When one of you wakes up from his sleep, and performs ablution, let him blow his nose three times, for the devil spends the night in his nostrils," as found in Sahih al-Bukhari 3/1199, and in Sahih Muslim 1/212. See: Tabyin al-Haqaiq 1: 6-7, Majma' al-Anhar 1: 16, and Badai' al-Sanai' 1: 23-24, and Allah knows best.