Can This Coin Be Cleaned?

The two methods that I have been most successful with are the distilled water soak and the olive oil soak along with mechanical cleaning. I use a silver pick, brass pick, and diamond dusted dental pick (600 grit). Use tiny cicles.

I would start with distilled water (change the water every couple of weeks). If that does not work switch to olive oil. IMHO I think that the coin on the bottom left should clean up. From the pics the top of the coin looks restorable to me.

I took one that was cover in what seemed like concrete and soaked it in PB Blaster for a few months. Did this after water and a year in olive oil failed to do anything. I checked it every week or so until I was satisfied that I could get the rest off with dental and tooth picks. Worked very well and did not harm the patina.

Yes.....do tell! What is this PB Blaster?

There is a lot of promising detail on that coin--good luck!
Has anyone here researched what museums/convervators use to remove hard mineral deposits?
From what I've read, a lot of encrustations are lime-based, which basically produces concrete.
If lime can be removed without attacking bronze, that might be pretty effective.
Just thinking aloud here--I ought to buy a cheap crustie and expirement.