The water kills the friction material (basically paper with glue and such) which makes it debond from the steel backing. If what you have on your fingers feels like overcooked cookies and crumbles then it is probably the material. I would get a good aftermarket converter before trusting your rebuild with this converter. It may clean up and it may not. If the donor vehicle had a 383 it likely has a decent stall converter in it already. You could just use that one too.