As mentioned, there have been many posts on acetone. To summarize: soaking US coins in pure acetone will not harm them, and may remove oils, plastic residue, etc. Use acetone once only; do not reuse it. Remember it's very flammable, and its vapor is explosive. It's miscible with water in all proportions and has very low toxicity. Small quantities can be put down the sink as long as you start the water running before adding acetone and leave the water running for a few minutes after done adding acetone. This procedure will prevent acetone from attacking plastic drain pipes and prevent explosive acetone vapors from forming in the drainage system. Don't pour acetone into a plastic sink though! For acetone containers, metal, glass, polyethylene, polypropylene, fluoroplastics (teflon, tefzel) are OK; avoid other plastics. For handling coins, avoid metal forceps; too easy to cause damage. You can use the pour-in, decant-off method and avoid using forceps at all. I use tefzel forceps for moving coins in and out of solvents. Tefzel is similar to teflon, but more flexible. Can't be hurt by solvents; can't hurt coins. Some ancient and non-US coins may be harmed by acetone. Some ancient coins, especially bronze, may have been repaired with glue, and acetone may cause them to fall apart. Some ancients have been oiled or lacquered. Removal of the oil or lacquer won't usually harm them, but they may look very different. For some, bits of thick patina may flake-off if the lacquer is removed. Some modern non-US coins, especially commemoratives, have been colored (anodized, enameled, etc.). I'd be hesitant to use acetone on them unless I could verify that it would be harmless. Cal
Acetone is capable of forming a harmful reaction with copper in conjunction with bright sunlight and high humidity/water present, which might be a problem if your numismatic workstation is unsheltered in the back yard at the height of summer in the Equatorial rainforest. I only know this from reading about research in areas unconnected to numismatics; I've never really tried to duplicate it because I tend to leave my coins alone when I'm already dripping with sweat.
As I said -- if a coin has a sweaty guy working over it outdoors in full sunlight, it has a problem. You've probably been in on the discussions here where at least one Long-Time Member swears that he's seen US copper coins discolored by otherwise-"proper" acetone treatment. It's hard to deny what someone else has seen with his own eyes, but those of us with chemistry backgrounds tend to think such coins changed because of something else going on with their surfaces.
It would probably be safe, but I still don't like it one bit, and don't do it with my own plumbing. I tend to burn off the leftovers outdoors in a metal can. It's not perfect, but it seems like the best tradeoff among various forms of pollution (and expense). The very best thing might be to pour leftovers into a metal can and take it to your local residential hazmat collection station, but that seems like a bit of overkill, and it's hard to know what they do with it. Acetone doesn't deserve the same attention as benzene or carbon tetrachloride or chromates.
Hey Cal, it does seem that most folks do use acetone for their coins, so I appreciate the feedback. I did mention MS-70 earlier in my post, but I haven't seen any responses for MS-70. Do you even use it, or is acetone just better? If so, what can MS-70 be used for if acetone is just plain better?
I wouldn't mind knowing the answer to that. I've read all the rave about MS-70 but have never used it personally. I am curious though if any of you have used it.
I bought MS-70 and after trying it on a few unimportant coins I have put it on the shelf and gone back to acetone. While acetone does not effect the coins , only the surface contaminants, MS-70 effects the coin. First it is, according to it's label, recommended for AU-BU coins to " restore the brilliant surfaces that remain under the tarnish and years of surface contamination that has accumulated on your coin." MS-70 will remove tarnish , patina, and toning and IMHO doesn't leave a natural looking luster to the coin. By the very nature of removing tarnish, patina, and toning, the manufacturer is telling you that MS-70 does react with the coin.. It is, again according to the label, recommended for Mint State or Proof coins, but the method of application would seem to cause hairline scratches on Proof coins. Again, quoting the label, "Soak a Q-tip with MS-70 and gently apply to the coin. Allow a few seconds for MS-70 to penetrate the contamination on the coin and then gently 'message' the surface of the coin with a Q-tip which has been soaked in MS-70" . The contents of the bottle appear to be similar to a regular metal cleaner and brightener, similar to the paste I use to clean my knife blades.
I have used MS70 on several occasions but only silver and gold coins. The 8 reales was encrusted with dirt n other things prior in crevices of the sun rays. It removed it and enhancedthe luster. I would only use on coins that in ur opinion unc. And use a qtip with it all over the whole coin. I posted coins i used it on before submitting. WARNING: if you like toning DONT use. It will remove or alter most or all toning in my exp. Edit: i dont have the before pics available on my phone sorry. But it did real nice. I have 3 coins being graded now i used it on. 2 silver 1 gold. Chris
From the Cambridge Dictionary... "Affect is a verb meaning ‘influence or cause someone or something to change’: The cold weather has really affected her health. New technologies continue to affect how we live. Effect is a noun that means ‘the result of an influence’: The pollution in the city had a bad effect on me. Most people these days understand the serious effects of smoking." Now that I got that out of my system, acetone is a solvent that primarily removes organic materials (PVC gunk). As a solvent it could also float off any dirt or inorganic stuff that is on the coin, particularly if it is held on by organic gunk. It should not affect metals in any way, but I hesitate to poo-poo the experiences of dedicated coin collectors and you should do so only at your peril. MS70 is mostly a solution of a STRONG base (don't get it on your hands and especially in your eyes) which will turn organic gunk into soap. It also has solvents that will work well to remove lots of other stuff (disclaimer...I've never used it).
Buy a bottle. There is probably some "secret" sauce added to it. If you do get a bottle, PM me. I'll tell you how/when we use it.
MS-70 contains potassium hydroxide and sodium sulfonate, among other chemical goodnesses. I wouldn't use it on mint state or proof coins or any copper coin, but some folks have found it useful for silver and gold. URL for the MSDS is ww.translinesupply.com/PDF/MDSSHEETS/MS707530.MSDS.pdf. Koinsolv (n-propyl bromide) should be fine; however, I have no experience with it. I still use Dissolve (freon 113) as a general purpose degreaser. Can't buy it anymore because it's an ozone depleter. I redistill my precious supply. For removing PVC residue, I use tetrahydrofuran (THF). It's the best solvent by far for PVC and its plasticizers. You may never have heard of it, but if you've ever worked with PVC pipe, you've smelled it. It's the main solvent in PVC cement. Cal
Acetone is a relatively harmless biochemical. Produced in your body and by bacteria; also metabolized by microbes. Small quantities, well-diluted are less polluting than any cleaner (toilet, detergent, oven, bleach, etc.), fertilizer, even softener salt that get put down drains. Microbes will metabolize it to water and carbon dioxide ... about as non-polluting as you can get. Burning it carries the usual risks of burning solvents. If you wouldn't burn gasoline, don't burn acetone; in other words, don't do it. There's always the chance a neighbor might call the fire dept. too. On warm days, small amounts can be poured on an outdoor, private concrete surface but not near sources of ignition or under a roof. It will evaporate in few minutes. Cal
I'm really surprised to hear that so many of you are using acetone! I have an old coin album that has quite a few sticky coins from the soft plastic. I guess I need to look into acetone more..
The only argument against it is the same for just about any liquid you might apply to a coin. If the coin in question has cruddy surfaces, there will be still-exposed areas which have aged at a different rate than those covered by crud. If you successfully remove the crud, the surfaces underneath will look "newer" than the rest of the coin and it will look obviously cleaned. In a lot of cases that won't matter, but it's wise to always consider the question, "What if I am successful in removing this stuff?"
This is very true sometimes with corrosion vergidis (sp) it will leave new looking copper /bronzeblazing out in a background of toned copper/bronze after being removed with things.
I have heard & have seen (before-after done out of my sight) that it is very easy to fix the problem with copper/bronze you write about. Sure wish "they" would tell me how to do it.
I hope our return to on-topic discussion has effected some improvement in your negative affect. (And I hope you read all the way to the end of dictionary entries!)
