Proper acetone procedure

Yep. I guess you're more likely to encounter layers or wads of organic stuff that needs acetone or xylene, just because the water-soluble stuff tends to come off in sweaty palms or on damp counter-tops. But water's cheap, safe and easy, and some of the stuff it dissolves (acidic or chloride-bearing salts) is particularly dangerous to coins, so there's really no reason not to use it first.

 

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I'm going to have to try some distilled water that was boiled at home. The water I use comes from the Great Lakes so it's fresh and clean as it is, not hard water.

Anyway, does anyone know if cloudy ammonia damages coins?

 

Remember that boiling water isn't the same as distilling it. Boiling just kills bacteria and drives out gases, but doesn't get rid of any dissolved solids.

I wouldn't let cloudy ammonia anywhere near my coins. There's no guarantee what puts the clouds in it, but it's probably nothing good for coins, and ammonia itself isn't very safe -- I'm not sure it would actually attack coins, but it likes to form "complexes" (loosely bound chemical compounds) with metals like copper and silver, and I'd worry that it might cause some etching, especially if mixed with the wrong "other stuff". It'll definitely attack zinc.

 

Distilling involves condensing the water not boiling. When you condense the water from air, it leaves the dissolved salts behind. It is the salts that damage the coins. And before you get any more ideas, condensing water from room air introduce both carbonic acid and nitric acid. Acids love to eat coins.

And ammonia (more explicitly ammonium hydroxide) eats copper. 99% of our coins contain copper.

 

I'll just get some of those gallon-sized distilled water jugs at the store then.

How about methyl ethyl ketone (MEK)? I see it tossed around on the 'net, and that it should only be used for copper coins. Does anyone know for sure that it's safe? Is it bad for silver coins?

 

As long as it's pure, it should be exactly as safe as acetone -- it's chemically almost identical. It just evaporates a bit more slowly, which makes it a bit safer with respect to breathing and fires.

 

MEK is pretty good stuff, but no better than acetone. If you got some, use it.

 

Will MEK target one-for-one the exact same stuff on a given silver coin that acetone will target? Or, is it that for most residue on coins, acetone and MEK are practically the same, but there are some one-off things that MEK will remove that acetone won't, and/or vice versa?

Also, would I use MEK prior to Xylene? Consequently, would the order below be the technical and comprehensive order of polarity to conserve coins?

1. Distilled water
2. Acetone = MEK (?)
3. Xylene = Toluene (?)
4. Acetone = MEK (?; Optional)

 

AFAIK, MEK will behave exactly the same as acetone. If you use one, little reason to use the other. The order of application isn't particularly important, except I would always start with water, tap or distilled.

 

Acetone Structure:



MEK

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MEK is slightly less polar than acetone due to the addition of a methyl group. For coins, I don't think it'd make any difference compared to acetone unless you get lucky and it better matches the residue (i.e a less polar residue). The polarity order would be:

1) water
2) acetone
3) MEK
4) xylene

 

I cry Foul! We are not discussing haze on copper in this thread.

 

Yeah, you are correct. I thought this was the thread about removing haze from proofs.

 

Now Doug, no leniency for age, most give fake ages when they join anyway

 

Yeah, and before I knew how strict this forum was I posted that I was a twenty-something female working at a TPGS looking to marry a grader! The only place I ever lied about my age that I can remember after my teens was on MATCH.Com. I claimed to be ten years younger (lie), very active (true), and informed the ladies reading my profile that if they did not have a waist - they shouldn't reply.

 

I have a proof state quarter that had a fingerprint on it. I tried acetone and no go, it didn't take it off. I have a bottle of MS70 that I never used. I followed the instructions and soaked a cotton swab with the liquid and gave the coin a gentle swipe. I let it sit for a few seconds and washed it with distilled water. Fingerprint gone, and a nice mint luster was left.

 

And that was a total waist...

 

Everybody makes mistakes.

 

Yes, the so-called "sniffer" (can be an analytical instrument called Surface Enhanced Raman Scattering, SERS http://jes.ecsdl.org/content/129/8/1716.short or even by Infrared reflectance spectra, http://www.sciencedirect.com/science/article/pii/S0010938X70800269 ) will detect films of benzotriazole (BTA) on the surface of a copper coin or in a coin that contains copper (such a 90% silver coins). BTA does not "disappear", it creates CuBTA by covalent bonding with the copper atoms.