I recently found a really beat up 1906 V-nickel. My red book is a little old (2002), but at MS-60 the nickel would be worth $65. At G4 it is worth $1.25. This would be pushing it to claim this nickel was G4.
When it came out of the ground, and after I soaked it, it was still a rust brown color. You couldn't make out hardly any of the Liberty Head side except part of the date. I felt like this was a good candidate for the "salt and vinegar" and it cleaned up very well. It still had a scarred up obverse, but you can tell it is a V-nickel and you can read the date now.
If it had been 1885, 1886, 1912, or even 1888, I would have left it like I found it or let a professional clean it.
I have often heard that you should never clean your valuable coins. However, I had a professional coin collector tell me that all collector coins are cleaned by someone, that you just need to know how to do it. I've read a few books on cleaning coins, and at some point it is necessary to clean coins, especially silver, to keep them and their value from degrading. Even keeping them in the specially made containers can allow them to degrade.
So I find myself somewhere between being moderately concerned about the condition of the coins that I have already found and how to take care of them, to being bent on finding old coins that have been degrading in all sorts of dirt for over a hundred years that have never been taken care of.
The main thing I try to avoid is further degrading the value of a really valuable coin.
The irony is I have never sold any non-clad coin that I've ever found. I don't know many people who do. I only need to preserve the value to suit me I guess. Sometimes I think us detectorist really don't look at the big picture. In the mean time, I'll keep careful care of these coins as if I'm going to sell them tomorrow even though they will still be here when I'm gone.
Others may look at it completely different of course.
But at the beach two weeks ago I found a beautiful 14K gold St. Christopher medal. I didn't even have to touch it. It had been scrubbed by the sand and washed by saltwater. Basically, with the addition of vinegar, that is the way I cleaned my V-nickel.
HH Alton