I too, hava a Nero sestertius with a bothersome patina. It has a nice portrait and chocolate brown patina, but the bare metal shows through at several points on the bust, which I have always felt somewhat detracts from it's beauty. I have heard about Deller's, and have wondered if a small bit might might do the trick without compromising or cheapening the coin's look. Here it is for reference, any thoughts, opinions, or suggestions?
Deller's is sulfur based and causes surface oxidation. I think it would turn those bare areas black. As a result, not sure I'd use it on that coin. From a personal perspective, I think that coin is beautiful
as is and wouldn't do anything to it.
Having said that, I know Jax
comes in different colors, but I don't know the process through which it works or what it looks like when done. Maybe someone else can chime in on that.