WYNTK: About Coin Dipping, Or What I Learned From Many Mistakes.
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Coin dipping of any coinage material should be approached with extreme caution. Whether a collector dips copper, bronze, Cu/Ni clad, silver or gold coinage there can be unexpected, less than desirable outcomes or unpleasant surprises. This is especially true with treating or dipping older, classical circulated coins in commercial, acid-based, jewelry or coin cleaning solutions. Copper, silver and gold coins can sustain permanent toning and surface damage plus, copper color changes as a result of careless or unknowledgeable dipping.

 

I can say unequivocally, that I personally have ruined more body bagged or doctored Morgan dollar silver coin surfaces, both circulated and uncirculated, plus circulated cents with Jeweluster than with any other dipping solution that I can even recall at his point. IMHO, I will not use Jeweluster straight or diluted, for cleaning anything that I value more than an empty beer can. Jeweluster has single-handedly, stripped, removed remaining luster, discolored, blackened, yellow toned, turned copper pink and ruined more coins in the hands of collectors than any other substance except maybe rubbing coins in baking soda or with Flitz abrasive cloths.

 

I have used acetone, M.E.K., methylene chloride, alcohol, Freon (CFC, no longer available), HDFC (also banned), Ivory soap and warm water to soak off detritus, Verdigris (from PVC exposure to bronze or copper), (coin doctor) cigarette smoke residue, fresh fingerprints (before skin oil, acid damage), Goo-Gone and olive-oil residue. These solvents will also sometimes also remove a doctor’s (except epoxy or Bondex) putty job from a coin as well. Acetic acid will remove epoxy, by the way. All of these solvents work and have their place. Any aromatic solvents should be, however, be used outdoors with good ventilation because most (except CFC and HCFC) are highly flammable and are (on MSDS sheets) considered carcinogens. These solvents also are heavier than air, accumulate, build upward from a floor and possibly smother a person in an enclosed, improperly ventilated area. I can remember (in the old days) pulling unconscious factory workers out of methylene, solvent-Ultrasonic cleaning rooms and performing CPR because the oxygen in the room had been replaced by heavier-than-air, solvent fumes. These fumes were later removed via engineered extraction, filtration and recycling systems employing low level, plenum extraction ducting to move the fumes by moving them into a distillation, recovery process room, far from worker areas.

 

Branson and other companies also sell ultrasonic cleaners for their ultrasonic cleaners. These machines will remove soil from circulated coins. However, I wouldn’t put an uncirculated or valuable coin in one of these ultrasonic tray baths.

 

Regarding the use of acids. I have used glacial acetic, dilute hydrochloric and sulphuric acid on silver coins (doctored Morgan dollars again) with mixed results. Caution dictates that all of these stronger acids should be used under fume hood tables with full safety garb, rubber gloves and face shields only by people trained in handling acids. Well circulated and tarnished Morgan’s when wiped with these acids do not usually show much surface change difference after treatment, except for perhaps tarnish removal, unless the coins are soaked in the acid for some period of time. Uncirculated pieces can and will sometimes develop a shiny, unnatural looking, pebble grained surface if overexposed to acid. I do not recommend using these acid for cleaning any coin surfaces of value.

 

The only product which I have used with some success on silver coins is MS70 which is available from Betterbuilt Chemicals in small bottles. MS70 is strongly, not recommended by the manufacturer for soaking coins (read bottle directions). I have used it by wiping with a drop deposited on a Q-tip, and rubbing lightly on doctored (AT) Jefferson nickels, Cu/Ni clad coins, common-date, low value, uncirculated, Peace and Morgan dollars to remove unsightly toning. It does brighten these coins somewhat but may require vigorous wiping to remove dark toning spots. These are dark spots which I, personally, will not take a chance wiping hard enough to possibly hairline a coin. I will not use anything to clean valuable, classic copper, silver or gold coins. Stripping 100 years of slowly accumulated toning from a classic gold coin is a crime against nature! I would strongly recommend sending classic coins to NCS for any restoration work that you feel absolutely needs professional restoration or any aggressive toning removal. Otherwise, I would leave the coin as is, spots and all.

 

There has been a great deal of discussion, pro and con, on this board regarding the use of MS70 on copper or bronze coins. IMHO, MS70 should not be used on copper or bronze coins worth more than face value. Many of these uncirculated copper and bronze, classic coins have turned a tell-tale, unnatural, blue after being wiped with MS70. IMHO, this toning is AT and should not be encouraged. Some cabinet toned copper and bronze coins will turn lilac or light blue from long storage and IMHO, this is acceptable, “natural” toning. This all is only my personal opinion, based on more than (40) years of collecting and enjoying coins and should be taken as such.

 

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Great article some great warnings. I have used MS-70 on silver coinage and have had good results. Due to the slickness you have to be carefull not to drop the coin.

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This is pretty much anti-dipping reading with which I agree to, especially with pre-modern coinage. Dipping my be fine to remove hazing...but to improve a coins overall eye appeal, either a coin has it or it does not. A bath cannot not improve old coins.

 

I think this article needs to be posted in the coin forum for better exposure.

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Fine, I put I here because this article where these topics have always been introduced. It probably will be moved to the WYNTK section of the board anyway fairly quickly. IMHO it is a coin tangent because it is not specific to U.S. coins.

Edited by Oldtrader3

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An outstanding post, Charlie! Your engineering background added a lot of spice to it. (thumbs u

 

Most circulated coins should not be dipped at all. However, in a few, rare cases, a dip in a mild acidic solution can drastically improve a coin with ugly toning. I just dipped my 1835 AU58 dime and it is far better looking now than before. I can now see the gorgeous luster that was hidden behind mottled toning and there is no surface damage at all.

 

I find that MS70 works best on AU and better coins as well. It can really reveal the beauty and luster that maybe lies hidden within.

 

EZest is the best acidic solution that I know of. It kind of smell like kindergarten paste. :þ Don't eat it, though!

 

It should also be mentioned that care should be taken when rinsing and drying the coin!!!

 

Rinse thoroughly and pat dry with soft cotton cloth, etc.

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An outstanding post, Charlie! Your engineering background added a lot of spice to it. (thumbs u

I agree.

 

It should also be mentioned that care should be taken when rinsing and drying the coin!!!

 

Rinse thoroughly and pat dry with soft cotton cloth, etc.

 

This is what I am really interested in as this is what can sometime prevent a coin from being graded after a dip. Just like I would have thought that using a q-tip would leave scratches on a coin.

Edited by Dwaine

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It depends, MS70 is somewhat lubricious which protects the coin surface from scratches with the Q-tip cotton as long as you don't rub vigorously to jam the cardboard stick into the coin surface. I do not even rub hard enough for the cardboard or plastic stick inside the Q-tip to even bear on the coin's surface. I hold the Q-tip shaft nearly parallel to the flat surface of the coin so just the cotton touches the coin. This is the point of using a lubricated Q-tip and not pushing on the stick. Only the MS70 and the soft cotton should very lightly contact the coin's surface. You are trying to wet the surface and rub very lightly. I would not necessarily recommend using a Q-tip with other dip solutions, using a wooden Q-tip shaft or certainly not bearing any weight down on any Q-tip shaft.

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I ruined many coins using MS70 and a Q-tip in my rookie days. I don't advise it!

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Point well taken. I don't use it on any classic coins or coins with much value. Just on coins out of mostly mint sets that already are spotted.

Edited by Oldtrader3

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I thought I'd tell on myself a bit..if it helps someone else avoid the same mistake..

 

I have tried dipping away haze and "milk spots" on a proof or two..never with any success. At best it remained unchanged, at worst, the problem/haziness became even more pronounced.

 

At the most now, I'll try to remove surface contaminants with a tiny bit of acetone..if it doesn't work, then I'm assuming that the surface/finish is permanently affected and I leave it alone..

 

Any thoughts?..Anyone else actually figured out how to remove milkiness from your proofs without etching into the metal?

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An outstanding post, Charlie! Your engineering background added a lot of spice to it. (thumbs u

I agree.

 

It should also be mentioned that care should be taken when rinsing and drying the coin!!!

 

Rinse thoroughly and pat dry with soft cotton cloth, etc.

 

This is what I am really interested in as this is what can sometime prevent a coin from being graded after a dip. Just like I would have thought that using a q-tip would leave scratches on a coin.

 

Again, does not dipping, etc, ruin it for grading?

Thanks!

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Ugh. So, there's really no way to remove the ugly, ugly hazing from proof coins 1968-up? Silly, cheapo US Mint plastic.

 

 

The haze on 1968-up proof coins is grease from the mint that is reacting with sulfur in the air and in mint packaging. It will come right off with proper conservation techniques, and you NEVER need to dip such a coin!

 

Dip should be a last resort, not the first line of defense, as so many misinformed people assume it to be. There are MANY other completely harmless chemicals to use. Dipping is an extreme measure that eats away a layer of metal, and should be reserved for cases were a coin has irreversable surface damage.

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hi there, this is an older thread but i have a solid question that needs to be answered. can any one help. recently i bought a 1857 o seated quarter au 58 easily. it is a beautiful coin. i sent it in to n.g.c. for grading and it came back au details improperly cleaned. now it does not have any scratching at all even under high magnification. so i am assuming some one dipped it and left residue. is there anyway to remove this residue so the coin will grade out?

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hi there, this is an older thread but i have a solid question that needs to be answered. can any one help. recently i bought a 1857 o seated quarter au 58 easily. it is a beautiful coin. i sent it in to n.g.c. for grading and it came back au details improperly cleaned. now it does not have any scratching at all even under high magnification. so i am assuming some one dipped it and left residue. is there anyway to remove this residue so the coin will grade out?

 

Get some pure acetone from a hardware store, not fingernail polish remover. Dip the coins in for 10 mins (use tongs). Then bathe the coin in water for 10 mins, making sure to shake the coin around to remove the residue. I've used a product called Verdicare that removes verdigris.

BadThad seems to be an expert at this, so I'll wait for him to chime in. :)

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I have used acetone, M.E.K., methylene chloride, alcohol, Freon (CFC, no longer available), HDFC (also banned), Ivory soap and warm water to soak off detritus, Verdigris (from PVC exposure to bronze or copper), (coin doctor) cigarette smoke residue, fresh fingerprints (before skin oil, acid damage), Goo-Gone and olive-oil residue.

 

Wow. I've never heard of Freon being used. How did you end up trying that? I know people who work for an HVAC manufacturer and are pretty much around or breathing some amount of it every day You mentioned MSDS sheets. Its sheet claims it's a relatively safe material, but I've always had doubts. One thing is for certain, it forms a lethal gas when heated. What was the effect on the metal?

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I worked in a Medical Devices plant where we mixed Ethylene Oxide with Freon (and later HCFC) in sterilizing chambers to treat polyester (Tyvek) and poly packaging. We used to use a million pounds a month of Freon and restilled it to reclaim almost all of it. The still was designed and built by engineers that reported to me.

 

I can not get it now with the Montreal Protocols in place. Plus, I am retired.

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