Seiko 7A38 - by the numbers

I have a very rusty 7a28 movement. I will try to clean it up and use it as a challenge to see if it is possible to save. When it comes to removing rust, electrolysis works very well, but not for stainless steel. Do some of you know what type of material the anti magnetic shield and main plate is made of?  Is it stainless steel, plated iron or something else? Have some of you cleaned a rusty anti magnetic shield on 7a series before?

I have, on a couple of occasions, with a reasonable amount of success. Left it to soak in WD-40 - for a L-O-N-G time.

See this thread: http://www.seiko7a38.com/apps/forums/topics/show/9272911

B.A.D. 7A38 movement - back from the brink. Well, maybe part way, anyway ....