How to Restore this German Iron Cross??

[Capncrunch]

So, a little backstory, I dug this Iron Cross (a 1913 Class 2, I think- after a week of white vinegar and scraping) in a ditch, beside a road in my hometown (NW MO).
Obviously, I have no idea how long it's been in the ground, but being made of iron, it is in terrible condition.
I have two issues on cleaning it:
1) It has an iron core, but an 800 silver rim, so I am afraid to use some methods of cleaning.
2) It is difficult to get anything to 'scrub' or scrape the rust from the iron- without damaging the silver.
I am hoping someone else here has encountered this type of situation and resolved it, without damaging the silver trim?
I considered trying electrolysis (which I have never done before), but fear that it will 'eat' the silver?
Any good ideas/info folks?

Also, for the WW2 relic experts- this cross is approximately 1.5" across, does that make it a Prinzen version? I can see some of the details on the 'front' of the cross, will there be a flat back, or will it have the same design as the 1813 ICs on the back?

Thanks in advance for any input, and God bless!
John

 

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