Sayyiduna Walid bin Uqbah (may Allah be pleased with him) said: When the Prophet (peace and blessings be upon him) conquered Makkah, the people of Makkah began bringing their children to him (peace and blessings be upon him), and he (peace and blessings be upon him) would pass his hand over their heads and supplicate for blessing for them. I too was brought to him (peace and blessings be upon him) while I was wearing khaluq, so he (peace and blessings be upon him) did not touch my head. Nothing prevented him (peace and blessings be upon him) from doing so except that my mother had perfumed me with khaluq, so he (peace and blessings be upon him) did not touch my head only because of that khaluq.
Imam al-Tabarani (may Allah have mercy on him) said: Zayd bin Abi al-Zarqa' narrated it like this, from Ja'far, from Thabit bin al-Hajjaj, from Abdullah al-Hamdani, from Abu Musa, from Walid bin Uqbah, whereas the correct version is that this narration is from Abdullah al-Hamdani, who is himself Abu Musa, and he narrates it from Walid bin Uqbah.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18628