I had a corning ware baking dish crumble too, I took the stuff out of it, put it in the sink to cool off, didn't add water to it either, and it shattered into a bunch of chunky pieces.
All my glass dishes are really old now, I look for them in the thrift stores, they are heavier than the ones they make today but they have nice handles on them so you can grasp them easily and I use Spic and Span to get the really tough baked on gunk off of them.