I had the 'brain wave' of using the dish washer because the cases were full of material from were I had bead blasted them.
They went in a beautiful shiny new like silver and came out black.
I cried.

A really helpful friend, (by that I mean totally unhelpful and sarcastic git) pointed out that I should not have have used a 'Finish Ultra' tablet.

This must be some sort of learning curve thing!