Why can't you wash them? I know that musty fabric can be soaked & then dried outside on a clothesline, & you can't tell they were ever musty! But it's a lot of extra work for you. Maybe 4 people can each take a quilt & soak it & then return to you for quilting, since you're willing to do that for the group. Good luck in your final decision -- & please let us know how this turns out!