I have found a small piece of glassine paper especially helpful when mounting my work with hinging tape. I am able to press the tape onto the back of the pastel paper without fear of damaging my painting. The image below will show you what I mean. Always clean the glassine paper with a dry cloth before moving it onto a new area of a pastel.
Beware: Never drag glassine across your painting as it will smudge the work.
If you would like some more ideas using Glassine Paper, go to Hints at my website.