Thinking About Prof. Cleaning This Coin. Is It Worth It?

It does look like a nice coin that could warrant conservation. I've seen some work done by experts to remove verdigris, with great results. I don't know the exact techniques involved - and I don't recall which posters, at another forum, did the magic - but it was impressive.

My only concern in this case is that the coin looks like it may be silvered - although it's hard to tell in the photo. I would hope that any treatment for the verdigris would preserve and enhance any indication of silvering. But I have no idea about these things.

I would recommend making a solution of sodium sesquicarbonate (very easy and cheap) and soaking it for a few days at room temperature to remove the green.

Here's an article with steps to address bronze disease.

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

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