So is toning a process that can be slowed or stopped or prevented in anyway or if all else fails cleaned ? and does affect the value of bullion ? lets face it everybody like a pretty coin to look at
If bullion is your purpose, ignore toning. It's neither friend nor foe. If numismatics is, well, the answer is more complicated.
I do believe I recall that, yes. But it's been a long time since I've seen one specifically tied to bullion per se.
Negate? Not really, but silver toned coins are kind of stable. So much depends on climate. Where I live, with the Chesapeake Bay acting as a constant humidity pump, nothing is ever stable. Copper is never stable, period, because a good portion of the toning is due to oxygen rather than sulphur. Cupronickel is funny. My experiences and Lehigh's are 180 degrees opposed. .999 silver is VERY active and tones ridiculously. .900 is more stable.
Now just from a chemistry standpoint, nickel is pretty active, copper is moderately inactive and silver is quite inactive. Interesting.
Slowed, yes, by "slabbing it", either in an air-tite capsule (and yes, they do make them for bars too, I use them), or for a coin sending it to a TPG. You can also use a desiccant gel pack in your storage vessels (look at other threads here and you'll see some discussions) to help wick away moisture and humidity. Stopped, no. Cleaned, yes. A dip in Acetone (and please, use pure acetone NOT nail polish remover) will usually remove most if not all light surface toning (tarnish). There are other cleaners such as MS70 which will also work, but they are harsh on the metal. If it was a proof finish, anything other than acetone (and even improperly dipped in acetone) you can kiss that proof finish goodbye. If it's bullion, honestly tho who cares? Personally I like toning on coins and don't mind it on my bullion. Even those "nasty" AT ones can be rather interesting and eye-catching if you understand and appreciate it for what it is.
This goes against most of what I've read here, posted by metallurgists as well as experienced collectors. Acetone can't dissolve metal sulfides or oxides, nor the underlying metal itself.
You are correct in that it won't dissolve the underlying metal. I was mainly referring to if the dip is not done properly you could end up with spots on the finish which may or may not come off (should come off) with a subsequent dip. Truth be told, I haven't personally dipped what you'd consider a "truly toned" coin, as I prefer them and wouldn't try to "ruin" them . What I have dipped are a number of Ikes, especially the proof ones where there's a hazing on them, which i usually considered toning (that typical blue hue under light you'll see on them). The acetone will remove that usually no problem. I've heard the converse of you, where acetone will remove surface toning, but if the toning has progressed too much it won't work. I'm curious now, I'm going to have to go find something in my collection that's toned and I don't care about and try it there.
So does aluminum. Surface chemistry is a difficult field. And actually we have seen some beautifully toned nickels on here.
To prevent toning for .999 Silver put in ziploc bag with a silica pack inside with it. That works for me.
For me a few months, others on this board have done it for years. I did an experiment in my safe. I have the silica packs that change from blue to pink when they are spent. I put one new silica pack in with a few of my ASE tubes in the ziploc bag. In that same safe I put a new silica pack by itself. The one in the ziploc bag is still blue as it was the day I put it in and the one outside is pink. It has only been a month.
Oh, okay, for me, it ain't "storage" until the number of years goes double digits. Up 'til then, it's just hanging around.
I have never seen MS 70 damage a silver coin. Copper I would be more cautious about using it on, but silver should be perfectly fine. Plus if he's asking about true bullion that basically trades for melt, it really doesn't matter how harshly it's cleaned the metal is the value.