Pillow cases work, they are good in a quilt. I am doing one now, with some pillow cases I found when cleaning my mom's linen closet. Some had to be pitched, I am sure they are not all 100% cotton, but sentimental means a good deal so am using them here and there. It is a quilt for my bed, will not be overwashed as in for a quilt I might do for my grandchildren or kids for that matter. Some of the old pillowcases, especially the old embroidered ones are very nice. Some time ago, I sewed two quilts completely from pillowcases/sheets from yard sales and thrift stores. They turned out well and most of all, I am happy with them. And if I am happy, not so concerned with what someone else might say. Have fun with it.