I have done the fabric both ways. I always wash new fabric - use my pinking cutter on the cut edges. On the other, I use a mesh bag that is used for fragile underwear. I have 6 of the bags in different sizes and an HE washer. When I wash any of the fabric, I always put 3 color catchers in one of the mesh bags to catch any washed out colors. I put the squares-jelly roll strips- layer cakes - fat quarters in the mesh bags and wash them with warm water. When I take them out of the washer, I lay them out flat on the washing machine or on a sheet on the floor to gently pulling them bag to their original shapes and then when dry, I iron them (can still be slightly damp if you want). Depending on the company/quality of fabric, some of them may shrink slightly or a lot. Hope this helps.