Removing lacquer from a coin...

MrEureka

A few questions about removing lacquer from a coin:

Does anything work better than acetone? If so, what?

Once the acetone (or whatever you use) breaks down the lacquer, where does the lacquer go? Does it evaporate? Or does what's left of it settle right back down on the coin?

Sometimes, I've seen a spotty white residue left on a de-lacquered coin, which I presume is lacquer. Is it?

Do you have to rinse the coin at one or more points to avoid the residue spots? If so, what do you use and how do you do it?

Any other suggestions would be most welcome!

savoyspecial

it wipes right off

savoyspecial

sorry *lacquer not liquor

coinlieutenant

I've only done it once. But I double the cleaning.

Acetone bath for a couple of hours, then take it out and put right in another (fresh) bath for an hour.
Our mutual friend may know a better way..

coindeuce

Methyl ethyl ketone (MEK) is an effective lacquer solvent, and has an evaporation rate of nearly half that of acetone, which may or may not alleviate the surface clouding that you mention. MEK is far more toxic than acetone though, and requires extra precaution to eliminate skin contact and/or inhalation of vapors. I've witnessed Mint State coins that have been de-lacquered which appeared to actually have altered surfaces that I suspect were caused on initial application of the incorrect type of lacquer. There is a difference between the components of wood lacquer and metal finishing lacquer. I would have to believe that an uninformed collector could easily misuse wood lacquer on a coin for intended preservation.

Broadstruck

Forget chemicals... Just wipe some bacon grease on the coin and let Aki lick the lacquer off

Shamika

<< <i>Does anything work better than acetone? If so, what? >>

Most any organic solvent should work although most of them are unhealthy to work with.



<< <i>Once the acetone (or whatever you use) breaks down the lacquer, where does the lacquer go? Does it evaporate? Or does what's left of it settle right back down on the coin? >>

The lacquer dissolves much like sugar in water. Once the solvent (acetone) evaporates, flakes of lacquer will be left behind.



<< <i>Sometimes, I've seen a spotty white residue left on a de-lacquered coin, which I presume is lacquer. Is it? >>

Mostly yes. But acetone can become contaminated very easily and what you see may be some other product that had been in solution.



<< <i>Do you have to rinse the coin at one or more points to avoid the residue spots? If so, what do you use and how do you do it? >>

Once the solvent has dissolved the lacquer, a simple rinse in water should be sufficient.

amwldcoin

I use cotton quetips with acetone. The quetip seems to absorb what the acetone disloves. Usually takes several times. I just repeat until the quetip remains white. The quetip will not damage or scratch a coin(at least I have never scratch 1 but some people can break an avil with a rubber hammer! )...just lighty swab the coin.

PerryHall

Once it's dissolved use acetone to thoroughly rinse it. Acetone is inexpensive so use it generously to rinse it.

ricko

Shamika and PerryHall covered it.... I always like to use alcohol after the final acetone rinse, followed by hot, running water....never have an residues. Cheers, RickO

johnny9434

<< <i>sorry *lacquer not liquor >>

dont mix the two up and end up in the e.r. either

jmski52

There are various resins used to make lacquers. Nitrocellulose was the original type. A nitro type solvent (gun cleaner type) would probably work, followed by an acetone or MEK rinse or two. And then water.

Then they used various natural "drying oils" such as linseed or cottonseed. I believe that acetone or MEK would also be sufficient for these. A commercially available lacquer thinner will work if acetone or MEK results in cloudiness or white flakes. Then use an acetone or MEK final rinse. And then water.

Since they started using synthetic resins and called them "lacquer", it may not be as easy. A clear urethane would really be a problem - maybe a blowtorch would work. A clear acrylic could probably be tested with acetone or MEK.

The principle involved for eliminating a residue is called the principle of successive dilutions. Each rinse dramatically reduces the concentration of the contamination. Several small volume container rinses are better than one big volume container rinse. A Nalgene squirt bottle full of acetone, sold by any chemical supply house would work best.

Acetone and MEK both go to the liver, so use good ventilation. They also absorb through skin, so use some decent nitrile or neoprene gloves. No sense in getting all tox'd. Oh, and they are both really, really flammable so keep away from any and all "ignition sources".

These days, if I'm using any noxious chemicals, I just go out onto the driveway on a nice day whenever I'm worried about vapors.

coinkat

MrE

MEK is often used on bricks/cement. I would not recommend this strategy as the benefits do not out weigh the harm.

ColonelJessup

<< <i>I've only done it once. But I double the cleaning.

Acetone bath for a couple of hours, then take it out and put right in another (fresh) bath for an hour.
Our mutual friend may know a better way.. >>



Acetone is maybe $8 per quart in the hardware section.

This is always the best way to start. The lacquer hasn't gone away. It's now in solution with the acetone. This is the long wash. Still visible residue? You can get an ultra-sonic cleaning device for $75 on the Internet. Want to go further with the ultrasonic? I'm a bit neurotic (no Andy, don't start)) about optimizing my results on expensive coins. One in 500 coins will need this. Want to know more? Start a thread and I'll share my experience, as will others.

Thus the second bath, though I've never seen the need for so long a bath the second time. You're rinsing off a solution into which the lacquer has already dissolved. But why not play it safe and immerse a third time with more fresh acetone.

While not lacquer, PVC can easily be handled the same way.

I don't get the idea of rinsing it in water, but, if so, distilled rather than tap water or Dasani.

Last rinse/immersion might be a couple seconds in tri-chloro-fluoro-ethane (not to be confused with tri-chloro-tri-fluoro-ethane (Dissolve), which is no longer available.) but this is really expensive (about $25 for a small amount).

It's a very fast evaporator and is more flammable and more toxic through inhalation and absorption. To me not that big a deal based on experience, but a word to the wise. Never used MEK

The Que-Tip (cotton swab) technique is a good one, but requires a steady hand. I always put the coin in the acetone and then gently use the cotton swab while immersed in the acetone. You MUST NOT use swabs with plastic sticks. The plastic will dissolve some chemicals into the acetone. It's also more prone to scratching. Paper is the way to go, or wood (no preference).

I don't know about the white spots. I've never had the problem. Could be some form of ED. Coins that have been lacquered have been away from oxygen for a long long time. Sometimes oxidation occurs very quickly when exposed to oxygen, especially on copper. I'd never offer an opinion on the white spots that wasn't really a guess on this topic without the coin in-hand.

EagleEye bought a whole run of IHC proofs at a Stacks sale maybe 10 years ago. I was 4 seats away. I saw them at lot viewing. He took off the lacquer with acetone and the coins went blue. He was accused of using MS70 by ignorant people. Just very basic oxidation.

coindeuce

<< <i>MrE

MEK is often used on bricks/cement. I would not recommend this strategy as the benefits do not out weigh the harm. >>



MEK is a clear, nearly odorless chemical that has many applications. I fail to see how the application to bricks or mortar has any relevance to its use as a solvent on coins.

jmski52

Acetone and MEK are very close brothers in terms of chemical structure and chemical properties. MEK evaporates less quickly and it may be a little better for some residues, a little worse for others.

I'm not aware of MEK being used on bricks or mortar, although HCL (commercially available as muriatic acid) is used for brick cleaning.

CaptHenway

<< <i>I've only done it once. But I double the cleaning.

Acetone bath for a couple of hours, then take it out and put right in another (fresh) bath for an hour.
Our mutual friend may know a better way.. >>



I used the clean second bath as well, but just for a few seconds.

Since I was usually doing multiple coins at the same time, after the second acetone rinse I would set them one by one in the bottom of a wide, flat jar full of hot water to keep them wet until I was ready to rinse and dry them in a controlled manner one by one. I used hot tap water for the final rinse and immediately patted them dry. Then set on a clean, dry towel to finish air drying.

Once had a proof seated coin with a translucent, reddish substance on it that would not respond to acetone, alcohol or paint thinner. Finally gave up and decided to rinse the coin in water to remove the various residues. The reddish substance quickly dissolved in water! Could have been currant jelly for all I know!

PerryHall

Is it safe to use acetone with an ultra-sonic cleaning device as someone earlier mentioned here? I would be concerned that a spark from an electrical device could ignite the fumes.

ColonelJessup

I've never heard of a spark/explosion incident. And if anything close to that happened.. well, that's the kind of story dealers love to tell on themselves. I can imagine the end of the story being responded to with "Your eyebrows will grow back. How'd the coin come out?"

Based on the amount of acetone I put in the ceramic teacup that I put in the water that I put in the ultrasonic, I can't imagine it being in a high enough concentration when it goes gaseous to be a threat. Even with faster evaporators like trichlorofluorethane, the amounts being used are minute in terms of the volume of air into which the evaporation takes place.

I have personally put acetone in a metal spoon and applied a flame to the spoon. Ne problema. After the acetone ignited it burned with a mild flame.

I seriously think that starting a lawnmower in the garage with the gas can open carries a much greater risk of explosion that acetone in coin-related quantities.

On the other hand, if you see me at ANA w/o my eyebrows.......

relicsncoins

I wonder if goof off would remove the laquer without damaging the coin.

ColonelJessup

<< <i>I wonder if goof off would remove the laquer without damaging the coin. >>




Nooooooooo.

CalGold

Maybe you can chip it off with a hammer and chisel.

CG

jmski52

I seriously think that starting a lawnmower in the garage with the gas can open carries a much greater risk of explosion that acetone in coin-related quantities.

I wouldn't bet on that. Acetone is extremely flammable, as is gasoline.

ColonelJessup

<< <i>I seriously think that starting a lawnmower in the garage with the gas can open carries a much greater risk of explosion that acetone in coin-related quantities.

I wouldn't bet on that. Acetone is extremely flammable, as is gasoline. >>



OK, I'll take back seriously