My first grandchild is due in July. I am busy making baby quilts & crib sheets. I recently purchased both flannel and cotton for the crib sheets and both are marked as "unsafe for children's sleepwear". Is it safe to make cribsheets from this fabric? What fabrics are safe for children's sleepwear? I have a pattern for a baby's sleep sack and I want to make sure it is safe for baby to wear at night.