Need Help On Cleaning Artifacts

[Ger]

Does anyone have any ideas on cleaning heavily crusted artifacts from possible 1715 fleet? Found object approx.4 in long 2 in across and reads silver on meter .Theirs a small spot on object that you can tell theirs something inside,but have now idea on how to remove build up.Any help would be greatly appreciated...Thanks...
Here are the pic. I promised ,sorry it took so long...Thanks again...

 

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[Dave N Japan]

WOW...I have no idea! Anyway to get a x-ray that would work?

 

[99*]

The green looks like copper could be an encrusted spike I have seen silver coins go green from being near copper and bronze, get an X-Ray ..99*