I redid one my great grandma had made. It had been on my bed my entire childhood and was really worn out. Many seams were fraying. I cut narrow strips of fusible interfacing and put under the bad places. I then zigzagged with invisible thread over the seams. It looks pretty good.
I also used Retro Clean quilt soak on it when it was all finished. That stuff is amazing. It even took out blood stains from when I was a kid!