I do it different ways depending on the yardage. FQ's get tossed into the laundry tub with soap and hot water. Doesn't take too long to tell if it's going to bleed. Larger pieces go into the washer. Depending on the fabric, I will clip the corners or stitch the edge. Sometimes I just toss without worrying about it. I always use color catchers in the machine. I do my pieces one at a time, watching the water, and do it by color, light to dark. Honestly, I've never had a problem with the machine being unbalanced. If there was bleeding, I always go for a second round, and once in a while I need a third round. For me it's definitely worth it, because I usually react to fabric that hasn't been washed. I've never used a towel or sheet while pre washing.