You can just measure and cut it off. With many fabrics the printed pattern just stops before the selvdge in which information is printed. Just cut at the end of the printing with scissors. If I cut the selvedge off of long pieces like four yards I fold the fabric horizontally so that the selvedges fall together in folds; put it on my cutting board and cut with the rotary cutter. It is pretty quick to do and is accurate. Another option is to sure most of the selvedges extend into the areas that will be cut away when you trim your quilt prior to binding it.