Only for those of us who who dont know what we are dong (like myself). Most major dealers (and everyone else in the world, museums, etc) use electrolysis to clean coins and antiquities. In the right hands, magnificent. In my hands, destruction.
If you use a very weak solution of Bi-carbonate soda and Soda ash in most cases it will dissolve the green patina and leave the underlying brown alone, I have had a bit of success with this lately on coins with deposits, only should not be used if you have a nice green patina. Top photo before solution, my main aim was to get the green globs of around the altar, and below I left just a speck of green in case I went to far.
JA ... where do you find those great coin-examples? (I will be watching your next auction => yup, I'll be waiting to snag good ol' number 3!!) Oh sorry => no, I would not try to clean that gorgeous OP-example (it already has fantastic eye-appeal already) ... it's a total winner
Dont get too excited, its a replica. There is an outfit who sells them in bulk. They have been discussed before, though I cant recall the name.
LOL, thinking along same lines. Yesterday I googled them: $86 USD for 16 different versions! I - XVI...
ahahaha => of course it is Thanks though (if you find a 'real' example then please give me a heads-up)