this is where my opinion will differ......before I cut fabric into strips ( I personally do not like precut 2 1/2 inch strips as they have never been correctly cut, too narrow or wonky! ) I always use a LOT of Magic spray sizing and iron that piece of fabric from the right to the left, top to bottom, around in circles....any way I want to iron, I do....adding more sizing as I iron......then and only then will I begin to cut my squares or stirps. In the 20 pluls years of quilt making, I have found that this will ''shrink'' the fabric and I get almost no shriking or puckering when the finished quilt is washed and dryed. I do use color catchers as this will not stop bleeding fabrics but IMO, it will cause the weave of the fabric to ''tighten up' and give me a true cut of the fabric. For a lap/snuggle size quilt, I would use at least 1/2 a can or more. I just finished a Queen/King size and used 2 full cans......not only while pressing fabric before I cut but I also spray....lightly now.....as I am pressing the blocks after joining 2 pieces together. I also iron with sizing, the entire backing fabric, so it does take a lot of sizing but it is still less than a dollar at Walmart!!!!!!! and it does NOT gum up your iron.....