<<Second, years ago I used to do plaster cloth masks directly on the face of my students. Now that I am back teaching art at the high school level and while looking at art supply catalogs I noticed that plaster is no longer recommended for direct skin contact. Has health issues developed?>>
While I've never had a problem using vaseline and plaster gauze directly on a student's face, I've become more cautious. When I did this project at a summer camp this past summer, I used plastic wrap on the kids before applying the plaster gauze. While we lost a LITTLE bit of detail, it worked fine this way and I felt it was a safer alternative.
As you'll note in the pictures, some kids also did their hands and arms. I let them use vaseline and plaster gauze directly there, but I won't use it anymore on faces since the plastic wrap worked so well.