I use cotton rich sheets for my backing sometimes. Can't be a satin sheen sheet as that's too slippery for me. I love seeing what others have done using different fabric in their quilts. My husband's grandmother made a quilt using men's wool suits. We have several of her quilts and I dearly love them. She used what she had and rarely purchased fabric. I love the thought of that (being what pioneer women did all the time). That being said my personal choice is new 100% cotton. I would however like to make each of my kids a quilt from different clothes they had when growing up. A story quilt if you will and they are not all 100% cotton.