The fact that cleaning of the ears is not found in the traditions reported in Bukhari cannot be used dismiss wiping the ears as part of wudhu. The reason for this is that often narrators cite what is most important and leave out something, which was not considered as significant or even known to everyone. Wiping the ears is mentioned in other well attested traditions. To cite one: Abu Dawud, Nasa'I and Ibn Khuzaymath report on the authority of Abd Allah b.'Amr b. al-'Aas: While describing the Prophet's demonstration of wudhu, he said, "then he wiped his head, and inserted his index fingers in his ears, and wiped the outer parts of his ears with his thumbs".
Based on this and other evidence, scholars have concluded that wiping ears is part of wudhu. However, they disagree whether it is one of the essentials or simply a recommended practice.
Let me remind you of one crucial point for you to consider when studying such issues: the format of the acts of worship and purification as practised by the Muslims, belonging to the four schools of jurisprudence have been transmitted through reliable channels of transmission. So we must never question them by looking at a hadith or tradition out of context. The traditions are to be interpreted in the context. The practice of the community cannot be overlooked in arriving at sound interpretations of those traditions.