I'd like more informaiton about this also. For regular clothes ironing I really like to use sizing. And in the past I sometimes used sizing on sewing fabrics that I couldn't get the wrinkles out of after shrinking -- worked great and crisped things up. I had read a long time ago that you should never use starch for quilting as it will eventually draw bugs to your project. Then I heard somewhere else not to add spray sizing, because this is like the finish fabric manufacturers use and you want to wash it out. When I was working on my doll quilt, Kwhite kindly gave me a link to Sharon Schamber's online directions for putting on a binding. And of course she uses starch extensively as well as Elmer's School Glue . And it does wash out. I used both on the doll quilt. It washed out fine.
When I read this information about keeping a homemade starch mix in the refrigerator, that seems to suggest that it could go bad, and again drawing bugs might be an issue. And Klue, you make art quilts. Does using starch on projects you never wash affect them?