The Times has a profile of Don Gabriele, the Vatican's "chief exorcist." In it we learn that it is a messy job:
In many cases, he says, they vomit objects such as nails or glass. Father Amorth has a collection weighing two kilograms. â??You get used to being vomited over. I once performed an exorcism on a woman who managed to hit me in the face with a stream of vomit from the other side of the room â?? physically impossible.â?
Not that you'd expect the work to be pleasant...