I don't use anything. After prewashing all the chemicals out of my fabrics, I don't add any more back in. I know I'm in the minority, but I much prefer to work with the fabric in it's natural state , not force it into sunmission. My pieces do not stretch, warp or buckle; my blocks stay flat; and my quilts stay square...all without spraying something all over the fabric surface. It works for me and I'm sticking with it.
