Here's 2 Largies that I found last year that I actually had the common sense not to mess with.
The upper one, the 1853, looks kinda like yours. Really makes you wonder what would happen to it if you tried messing with the patina, cause you can see the porousness of the copper of the non-patina'd areas.

I wouldn't do it.
I've learned that the peroxide method works well for getting surface dirt off of Large Cents, but there's a fine line with that, and that line is going beyond the point of no return, where the peroxide could atually start flaking off the patina too, if your not careful.
Olive oil, which is GREAT for Indians, also has the potention to mess up Largies. It leaches into the coin, and over time, it can break down the coin, causing detail to slowly but surely flake off.
The bottom coin in my photo shows an 1850, with a very dark, almost blacklike patina. I was told by the elders in my detecting club, not to touch it, and that it was probably lost very shortly after mintage.
I'm starting to think that the best way to lightly oil these coins to clean and preserve them, is to use your own natural oils on them. This sound kinda gross, but after I get the basic dirt off a Large Cent, I'll rub it across my nose and Forehead, and let it absorb those human oils. That's all they were used to in their lifetimes before they were lost. "Greasy People".

It's preserved them until now. I wonder how many others have thought about this?!
