Years ago they used to make a quilt topper made from muslin. They embroidered a simple design of flowers etc. on them. It was about 10 inches long by the width of the quilt.They would hand stitch this to the top of the quilt so it would not always be in contact with the persons skin. They could take it off and launder it and not the whole quilt. Don't know what they were called. I have 2 that were made by a dear friends mother. This could be an option for your quilt.