If you work on drawings for a long time and do a small area at a time or don't erase once down, besides the protective paper (or a thin stiff plastic panel as I use to keep from getting hand oils on the paper so my pen doesn't work), carry a spray can of fixative to fix the drawing along the way.
Take a piece of scrap paper and keep it covering the drawing area that your hand rests on. That way the hand only touches the extra paper and not your penciled art.
