All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
We could not find any mention of the method of lot-casting used by the Prophet in any of the books and references available to us. It should be noted that whatever method used to draw lots is valid, be it by writing or otherwise.
Ibn Qudaamah wrote:
"Chapter on the method of lot-casting: Imaam Ahmad narrated that Saʻeed ibn Jubayr said, 'Lot-casting is done using rings; he cast lots between two people by putting their two rings in a piece of clothing and selecting the ring of one of them. Then, he said, 'This is how lot-casting is done; they (the parties) give their rings to be given to a man to select one of them.' Ahmad asserted that whatever the result of the lot-casting is, the decision is made accordingly and all the concerned parties agree on it as a final decision whether the lot-casting was done by means of patches, rings, or any other medium. Our late companions advised that it is better to use small patches of equal size, put them in the gown of someone who was not present when each participant chose his own patch and then have him choose one of them or have them covered with a piece of clothing (and each patch is put in a bunduqah [i.e. a small ball of wax or clay]), then it is said to him 'enter your hand and select a bunduqah of them'. Hereupon, he takes it and opens it to know what is written in it. This is the view adopted by Ash-Shaafiʻi." [End of quote]
Allaah knows best.