All I can tell you is what I do, and I do not was the fabrics I get for my block of the month. This is a popular topic here and each person has their own way. I don't routinely prewash any quilting fabric and haven't had any problems yet. Having said that, I recently needed to use a dark red for trim on an otherwise lighter colored runner and I did rinse it in warm water to check for running. It was fine, no running. I do wash finished quilts with a color catcher when completed. Also checking to make sure no seams are coming apart. To answer your last question, no I will not prewash the yardage for my BOM, either.
Last edited by suern3; 03-16-2017 at 03:16 PM.