I only use sizing. As mentioned before, starch is flour based and insects (especially carpet beetles [they're the bugs that leave the little brown striped tubes behind]) and rodents absolutely love starch. Try a heavy dose of sizing. Let it penetrate the fabric (wait a few seconds after spraying), then press. Magic Sizing is the brand I use and is very inexpensive, around $1 per can and readily available in grocery stores and the big box discount stores. Have never had problems with pests using sizing, have had problems with starch. JMHO...good luck whichever method you choose.
Anita