This preparation is preserved in an ancient Egyptian => magical papyrus from Thebes dating to the late 2nd or early 3rd century. This is my new translation of the original => Demotic text:
Translation
„The anointing oil you put to your eyes before you question the lamp:
You fetch some blossoms from the *eye* of the *raven* ,
you find them in the place of the garland seller, another manuscript says lupine seller.
You get them fresh, put them in a lok-vessel of glass,
you seal it very thoroughly for 20 days (and you store it) in a secret dark place.
After 20 days you take it out and open it. Then you find some testicles inside along with a penis.
If you let it rest for 40 days and then take it out and open it again,
you will find it has become bloody.
You then give it to a glass thing and put the glass thing into a clay thing
and you keep that in a place hidden at all times.
If you wish to make a god’s inquiry with the lamp with it, at any time,
then fill your eyes with this blood before you recite the recitation to the lamp.
Then you see a figure of (a) god standing outside the lamp,
and it speaks to you regarding the question you have.“
Translation by Kirsten D. Dzwiza
The text is preserved in the => London-Leiden Magical Papyrus, Recto column 5.
I started an archaeological experiment based on these instructions, find out more about it here!