If yours are thin, use some kind of interfacing on them such as Pellon SF101. I repaired a quilt for a former co-worker that she had made out of various Harley Davidson bandanas. She had made the quilt for her daughter about 15 years ago and many of the bandanas had frayed and pulled out of the seams. Her daughter had collected them from different states that she had visited while traveling on her motorcycle. I had to completely take the quilt apart and interface each bandana with the Pellon and essentially re-piece the quilt top. It was quite the task but when I was done, her daughter essentially had a brand new quilt!