I appreciate all the suggestions so far. To address a few questions:
The fabric was from Fabricland, a decent chain that went out of business a number of years ago. Definitely NOT $9+/yd. as I couldn't afford that back then. LOL.
Because it's a wall hanging and handquilted, it was only washed maybe 3 or 4 times, but in regular laundry detergent.
The only light source is a skylight about 15 feet up, which poses access difficulty when thinking about a UV film. It doesn't shine any direct light where the quilt has been, but obviously is still a problem.