Believe it or not, I actually performed a very simple exorcism several decades ago as a freshly ordained Catholic priest.
At that time I became convinced that some kind of evil spirit moved into my mother's apartment. Something was there, something negative. I could feel its presence every time I was in the apartment. I don't know what it was, but back then I was a devout Catholic, so I believed it was the devil.
I had no idea what to do. I thought of exorcism, but had no idea how to perform one. Plus, I was scared, as I had heard stories of the devil really giving a hard time to the exorcists, even if they were very experienced.
So I asked an older priest who was my teacher, spiritual advisor, confessor, etc, and who also was very much into everything psychic.
Well, he confirmed all the horror stories, but told me there was a very simple exorcism formula that was safe for the exorcist. He said it would either work, in which case that would be the end of the story, or it would not, in which case more serious measures would need to be taken. The formula was in Latin, and went like this:
Exorciso te, immunde spiritus,
et omnes administros tuos,
in nomine Patris et Filii et Spiritus Sancti,
et in nomine beatissimae Virginis Mariae.
Amen.
I was to say those words and make a sign of the cross as usual with the "in nomine Patris..." section.
So, next time I was in my mother's apartment, I did say those words and made the sign of the cross. Immediately after, I heard very strong noise, then saw a flash of very bright light, and then everything was quiet and peaceful, and I never felt the presence again.
I don't know whether it was a product of a young priest's imagination, or perhaps makyo, or there actually was something. It still feels like something was there and the ritual actually worked. For whatever reasons. It is still spooky to think about it even after all those years.
And I still remember the formula even though I never wrote it down (until now) or never seen it anywhere since.
Incidentally, if Latin is not your forte, here is my translation of the formula:
I exorcise you, unclean spirit,
and all your assists,
in the name of the Father and of the Son and of the Holy Spirit,
and in the name the Most Blessed Virgin Mary.
Amen.