I'm guilty.. I annealed a few cases without cleaning the necks. The necks turned black and it won't come off.
Can they be saved?
It should be ok and if it isn't just chunk it and call it experience. We have all been there. It's very hard to do something that has not been done by others.
I clean my brass before annealing not only to prevent false indications, I also like to see the heat ring location and the consistency of it. A clean shinny case will tell you how you did, or if you over did the annealing.
J E CUSTOM