I think you just have to tell people that you can't accept quilts from homes with pets unless the quilt is completely and thoroughly cleaned. Your health is too important to risk having an allergic reaction. It is the responsibilty of the owner to do this. You are not the one who needs to clean the quilt. That is the maker's responsibilty. You are doing your part by volunteering your time and skills, and they need to do their part by providing clean quilts.