I glue all my applique pieces and iron them to dry the glue. It holds the pieces down fast and washes right out with a little soak and then a hand-scrubbing in warm water. If you're using it for binding, it seems to wash right out when you launder it - even when you heat set it.
Try not to put the glue right *on* your hand-sewing line, though because it's tough to pierce with a hand needle.
I don't see any difference between the Elmer's Washable School Glue and the more expensive glues sold to quilters, so I just refill the tiny bottles from the big bottle of Elmer's.