(a) Amr bin Sulaym says: I bear witness about Abu Sa'id al-Khudri (may Allah be pleased with him) that he bore witness that the Prophet (peace and blessings be upon him) said: "The ritual bath (ghusl) on Friday is obligatory, and that one should use the siwak (tooth-stick), and apply perfume if it is available."
(b) Amr bin Sulaym says: I bear witness that the ghusl is obligatory; as for the siwak and the perfume, Allah knows best, but this is how I heard it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5954