thanks for your responses guys!
@daltonista...I'm not too sure if there could be any further conservation to this piece. My experience with dug coins over the past thirty years tells me that unfortunately this is about as good as it's going to be from now on.
It will always be detailed due to heavy corrosion from the ground.
Sadly in this case, all remaining detail remains mostly in the surface patina...remove that and you remove the visible detail left in the devices.
I'm happy to leave it the way it is for now knowing that fooling with it further will only destroy it.
Please keep in mind that I had to remove dirt and corrosion already ( via a soak in hydrogen peroxide which removes dirt etc but preserves patina) and for photograph purposes a thin coat of Renaissance wax to remove the dry look h2o2 leaves.
However, my methods may not be the end all here...I would be happy to get another perspective on preservation from other collectors.