Rainbow Toned Coins Prices

yes that is true but sometimes there is beautifull decay I guess

What type of $2 coin was this that sold for $200 because of the toning?

Rainbow-toned Morgan dollars often sell for a 2X to 10X (or higher) premium because of attractive toning. Here's an example of an NGC-certified 1887 Morgan in MS-65 that sold for over $1000 in a Heritage auction back in 2003. An ordinary MS-65 1887 coin should cost about $100. Wouldn't you pay extra for this coin? All it takes is two bidders who are both willing to pay a premium and the auction takes off.

Is this coin worth 10X the normal price? Some obviously would say "yes"!

Acetone WILL NOT remove natural toning(NT), it can remove artificial toning(AT) in some cases depending on what the coin was doctored with and it will remove most surface contaminants not bound to the metal itself. However, AT is a bad thing so you do not want it in the first place. Unless your "acetone" has a label that reads Jeweluster or E-Z-Est(these are the two substances commonly known as "dips") then NT will not disappear

My jar says E-Z-Est on the first line and Jeweluster on the second. Am I missing something?

And acetone is acetone, it comes in pints at the drug store or gallons at the paint store.

A blast white slabbed coin can be gassed in the slab.

Southern Yankee has a good point; toning is due to a chemical reaction between the coin surface and chemicals in the environment. If you can completely isolate the coin from further exposure to chemicals you can theoretically "fix" the level of tone. Complete isolation may not be possible, but a slabbed, naturally-toned coin kept inside a closed safe should be stable for many years. You can add protection by keeping a charged desiccant pack (silica gel) inside the safe to reduce humidity.

Carl, if you have too many of those nasty toned coins (like that NGC Morgan I posted) just send me an email and I can maybe take them off your hands. That way you won't have to waste money on acetone!

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Not just plain wrong. It will work and has for many, many years now.
Actually Acetone will remove toning sometimes and other times not. I just had a few Proof Lincoln coins that I purchased at the last coin show that had started to tone a decent amount. They were cheap so my first try was Acetone since it will not effect the coins. It did remove about 80% of the toning in a few minutes. I left them both in overnight and the next day they looked as if they just came out of a Mint holder. I've removed finger prints, dirt, toning, tarnishing on coins with Acetone many times. If that doesn't work after a few days, I normally just rinse with distilled water, blow dry and put away. Always remember that Acetone may or may not remove contaminations from coinage but will not hurt the coin either.
I've experimented on cleaning coins with just about everything possible over the last 50 ot 60 years and I'll just stick to what I know works.
And as to toning continuing in a slab, that all depends. If any slab is air tight, then very little to know more toning will continue. What some have done to make sure this doesn't happen is to use plastic types of glues on the edges of the slab to make sure they are air tight. Remember you need air or some type of gass to promote toning, tarnishing, etc. Toning will not happen in a vacuum either.