I have most success using 100% cotton fabrics however I have seen every fabric imaginable used in quilting. Back in the 70's my DMIL made quilts out of 100% polyester. Crazy quilts can be a mixture of any fabrics. The key is to prewash the fabrics before you cut them so that they won't shrink unevenly after they are quilted. If you don't plan on using the quilt and washing isn't going to be an issue, you don't have to worry about it. You will receive many more posts about this from people who know a lot more than I do so I am going to follow the post as well.