Cleaned As Much As I Dare.

Larger pics please!

Often to remove green corrosion from copper without picking you can soak in a solution of sodium sesquicarbonate.

Here are some articles with steps to address so-called "bronze disease."

http://www.worldofcoins.eu/forum/in....html#msg277

https://www.forumancientcoins.com/n...ze%20Disease

http://www.crescentcitycoinclub.org...0Disease.pdf

The solution of mixed sodium carbonate (washing soda) with sodium bicarbonate (baking soda) in distilled water is easy and inexpensive to make and is a helpful soak to remove green corrosion and stop its progress. The soaking can be done for a few days at room temperature instead of the hot water method described.

Formula for sodium sesquicarbonate solution:
10.6 g of sodium carbonate (washing soda) and 8.4 g of sodium bicarbonate (baking soda) dissolved in 100 ml of distilled water

Sorry about the pics, hope you can see these better.
Kev.

Very distinctive Ticinum style follis
Unfortunate that the reverse has the surface corrosion beneath
I think it best to leave well enough alone
The green lends 'character'
The pitting gives none
Soak in olive oil to darken a bit
But I would leave well enough alone

If the green corrosion is hard, not powdery then it's stable and shouldn't get worse. It's difficult to remove without damaging the coin. Underneath the green there may be pits/cavities so it's best left alone in my opinion. If powdery then it's bronze disease and needs to be treated. To stabilize I use a product called Verdi-care. You can get it at Wizard Coin Supply.