How To Clean A Natural Copper Nugget

General Cleaning native Copper.

1st Jun 2005 22:40 UTC John Steenbergen

Hi there skilful people,simply wondering if you can assistance with this niggling problem.I supose it has been asked many times over. I have a lot of Copper laying around both stuff that has gone through the smelter and besides large natural specimens of native Copper. Accept tried many ways of cleaning this and making it look pretty merely to no avail The strongest stuff i tried is the hydrocloric acids this cleans it but beautiful until i take it out then it turns green.I don't really go any stronger so this acid is at that place something on the market that volition take the tarnish and tiresome copper look off and brand it shine? Such a pitty to have these beautiful large specimens sitting hither and looking so boring and ugly. Perhaps some of you might know of a simple manner to clean these? John

2d Jun 2005 00:26 UTC Alfredo

Vinegar and a toothbrush is all I utilise to make clean the native copper pseudomorphs after aragonite from Republic of bolivia. I judge it would work equally well on any native copper. Cleans without leaving an unnaturally vivid surface.

2nd Jun 2005 08:xiv UTC John Steenbergen

Okay Alfredo i shall have a proceed the solid chunks and see how information technology goes but what near the wiry stuff? Any idea there? Some of the ones i have are like a birdnest. Thanks for the tip anyhow John.

second Jun 2005 14:thirteen UTC Alfredo

For "birds nests", use vinegar followed past an ultrasonic cleaner rather than scrubbing with a toothbrush.

Cheers,

Alfredo

2nd Jun 2005 17:xl UTC Chris van Laer

John:

Effort neutralizing the furnishings of acids by soaking them in a solution of mutual baking soda, then scrub/ultrasonic.

3rd Jun 2005 eleven:36 UTC Stone Currier

If yous have the nerve to try something stronger you can try an acid dichromate solution to clean copper. This has been used commercially by various mineral dealers in the past. Take some concentrated sulfuric acid, add together about v% by weight or potassium dichromate or chromic acrid and stir till dissolved. This will requite a thick night red/brown solution that will immediately eat up what ever it touches, but it will usually clean copper quite beautifully. This is a very dangerous reagent to utilise unless you know what you are doing. Use rubber gloves an acid resistant apron, and centre protection. Exercise not put or pour water into this reagent as it will exist converted instantly to steam and blow right back out at yous. It will completely eat up a clammy paper towel in just a few seconds. The copper is usually very bright and many people retrieve that information technology is simply likewise brilliant to look whatever where near natural. The copper merely needs to remain a short fourth dimension in the reagent and when y'all take it out you should immediately wash it off in large quantities of cold water. If yous want to make clean copper half breeds from Michigan I tin can give you another reagent to clean this material well if you want the silver to exist extra bright.

Stone

tertiary Jun 2005 14:sixteen UTC David Von Bargen

One of the problems with doing this is you actually should properly dispose of this cleaning solution (the chromium is what got a lot of plating concerns into trouble with the EPA).

3rd Jun 2005 22:57 UTC John Steenbergen

Hi ,give thanks you all for the tips but this stuff Rock discribes is a no no as information technology is just not worth the bother and chances are i would spill some knowing me. I call up i leave them as they are or dump them. I just idea there was a safe way,a solution of some sort that would practise the trick. After having a talk with my skilful friend from the Brisbane museum,he strongly advised me not to use the strong accids and reckons information technology could kill a person if spilled on any part of the torso. John

4th Jun 2005 15:28 UTC Mike

You lot might non be neutralizing your acid enough after cleaning it. If the hydrocloric is working good for cleaning, just try to neutralize the specimem more later on you're done cleaning information technology.

4th Jun 2005 23:01 UTC John Steenbergen

1000'twenty-four hours Mike,you lot got me going again,yous say in your letter (you lot may not be nutralizing ) What do you lot mean by this? As it comes out of the hydrocloric acid it is beautiful and shiny,but what happens next is i wash the acid of the specimen with plenty of water. And bingo within a affair of time the beautiful specimen turns dull again and starts to go greenish.So i idea well i'll set up this problem and sprayed it with hairspray. No good! Somebody said stick information technology in milk which sounded stupid, but ofcourse i tried. Then vinigar,then something else, but all failed.But information technology is a challence and am having fun. John

fifth Jun 2005 04:24 UTC Alan Plante

The dominion of thumb is that you demand to rinse the specimen in make clean running h2o for 3 times as long as you soaked it in acid. So for each hour of acid bath you're looking at 3 hours of rinsing in club to make sure y'all go all the acid off the specimen.

PS: There is a "Mineral Cleaning & Preperation" forum downward the menu a fleck. People who do a lot of this sort of stuff tend to read that forum and respond to queries - more so than are likely to choice up on a query placed in this forum.

Cheers!

Alan

5th Jun 2005 08:03 UTC John Steenbergen

Hey thanks Alan,y'all know something? I have never ever looked into this office of the forum and did'nt even know this was there. Now i tin come across that all the answers are there! How dopey can one go.

2nd Jul 2005 19:18 UTC Ted French

John,

I employ a l%/50% water and muriatic acid,

It cleans the copper very brightly. Then I neutralize the acid in baking soda. After they dry, I glaze them with clear spray paint. Afterward that they volition stay bright for many years.

Ted French

3rd Jul 2005 20:05 UTC Rob Woodside

Savages!!! You lot are ruining good coppers sticking them in acids. Fortunately in that location are a lot of well crystalized copper specimens that aren't wrecked with acid. Your activities simply make these more than valuable. I used to call back that Michigan silvers were acrid eaten, indistinct blobs; until I got an education at the Seaman Museum. At that place is little more disappointing than to see a harshly etced copper or silver.

27th Feb 2012 20:15 UTC david towle

We use a very old method to clean native copper nuggets. All the old collections in Michigan museums were originally cleaned with ketchup. The proccess I use is to put the nuggets in Muriatic acid for 10 fifteen minutes to remove whatever fe, dirt and calcite. then rinse in several pails of make clean water and backing soda, and then to nuetralize the resido acid. Yous tin can air dry them at this point to check them out or you tin go to the next pace. Take an ice cream pail and empty i or ii bottles of any ketchup into the pail. Put the nuggets into the ketchup, making certain they are all covered. Leave them in there for iv,v,6 days. I remove them with a large spoon with the holes in it. Then rinse off the kechup and allow them dry off. The copper will wait just like the first mean solar day they were made. A bright and natural shine. A few may some times oxidize back to a fuzzy dark-green. These will not clean up because of the mix of impurities in the copper. This ketchum method will keep your copper specimens in a like new natural condition for many years. I have some that we cleaned 20 years ago and they yet look like they were but cleaned yesterday! If some tarnish and y'all don't like the expect through them dorsum in the ketchup for a few days and they will be back practiced as new. While the nuggets are in the ketchup, cover the pail so the ketchup doesn't dry out out. The ketchup can be reused till information technology starts turning a chocolate-brown black colour or you lot need it for your hambergers. Yuk. The ketchup can be thrown out normally every bit in that location is no harmfull or dangerous chemicals used. The muriatic acid can be thrown out following the instructions on the bottle. I similar to nutrallize it with baking soda earlier getting rid of it. Besides we don't use vinigar as it tin can etch the copper. Making a valuable specimen worthless. So enjoy the ketchup cleaning proccess, information technology works. Dave

8th Oct 2013 01:32 UTC Dan the 2nd

I am new at this but...

I have several large copper nuggets, the biggest xxx lbs and the smallest 5.5 lbs

One of the pieces is copper and quartz. (sort of like a pokey birds nest)

I used hydrochloric acid on all of them (I did not dilute the acid), some came out quite nice, and but needed some buffing. Others came out all black and ruby. Saturday in the acid for 5 hours, and then out and into baking soda and water for xv hours.

I am having trouble getting the smoothen and luster and I cant figure it out.

I've tried vinegar and salt (brusque period of time)

and I also used tarnex (brushing on) later the wash in water, copper looks dull again.

I am starting to think, the only style to get proper shine is with a wire brush. (Which is tough labor and fourth dimension consuming)

I have done lots of research, but I have not found a clear cutting answer.

Anybody who can assist or requite advice, I would greatly appreciate it.

eighth Oct 2013 01:36 UTC Reiner Mielke Good

Copper that has a lot of arsenic in it cannot be cleaned with chemicals. This is not all that uncommon with Michigan copper, and is probably what you take.

eighth Oct 2013 02:28 UTC Paul Brandes 🌟 Manager

Unfortunately Dan, leaving your copper in muriatic for v hours probably damaged it beyond repair at present. Unremarkably, one never leaves copper in muriatic (if it is even used at all) for no more than mayhap v minutes to strip off carbonates IF at that place are no crystals visible. If one suspects any crystals then much milder methods must be used. Some other options include vinegar (once again watch the time it is in) and yes, even ketchup.

8th Oct 2013 14:05 UTC Dan the 2nd

Wow v mins merely in the acid, I will have to note that, thank yous.

How long? In ketchup? Or salt and Vinegar?

I practise have a crystalline sample. (it came out black from being in the acrid afterwards long while, I checked on it virtually every 15 mins, with picayune noticeable modify to its surface.

Any guidance is appreciated.

I think i only had 1 piece actually get ruined from the acid, because it etched the metal to the signal where you lot could run into what it was made of, lighter and darker pieces of copper.

over again thanks for the help in advance, this has certainly been a learning process.

8th Oct 2013 14:21 UTC Dan the 2nd

I want to add together a note most of my copper pieces, were covered in oxidation and ruby and black, before I even put them in the acid. This wasn't but a nugget with just oxidation, lots of hardened dirt and droppings.

Some of the pieces retained crevices that had big chucks of green oxidation even after being in the acid.

8th Oct 2013 14:35 UTC Dan the 2nd

Okay more questions. As mentioned earlier, I am a newbie and have a dandy bargain of learning to do. For the time to come:

1. Should I take a wire brush to it first, cleaning dirt and droppings and surface oxidation. (skip if adequately clean already???)

2. And so 5 minutes in acid (hydrochloric acid)?

afterward that's complete,

three. I let it soak in baking soda and water for fifteen mins? (3 times longer than acid soak)

iv. Then theoretically, I am ready for clear coating? (right?)
Note: this has never been the example for me, usually I have to retouch information technology upwardly with wire brush

give thanks you for your time - Dan

8th Oct 2013 14:42 UTC David Von Bargen Manager

"Should I take a wire brush to information technology first," - A wire brush could scratch the copper. If you accept any decent crystals on the specimen, you will ruin the value. Hosing it off is better (also pressure washing if y'all have the equipment)

eighth Oct 2013 fifteen:24 UTC Keith A. Peregrine 🌟

I use a dish scrubber to remove as much clay as possible after letting the rock soak in water for a while. There are some with very strong bristles and others with soft. I utilise both depending if there are whatsoever visible crystals present, copper or otherwise. Stiff ones are good for softening and removing tough crud, but they can damage crystals or soft material. In that case soft bristles are preferred.

As for cleaning copper, what I've encountered is when using dilute muriatic acid, the copper volition rapidly tarnish from nerveless from most Keweenaw dumps, a few don't. I've always attributed this to impurities within the copper though I take never tested that thought. The copper generally tarnishes to a tiresome brown or red brown color, sometimes almost black. A soaking in white vinegar commonly brightens it up, but as it dries it dulls once again. I take institute that the quicker you lot dry the copper, the more of a shine is retained. Even and then I've not succeeded very well in keeping a good shine. Copper Bright is supposed to coat copper to preserve the smooth, but I've only used the liquid version, didn't piece of work. Supposed to utilise the powder Copper Bright. Hope to obtain some soon when I visit the UP once more this weekend.

Curiously, freshly cut copper seems to retain its shine easily, which makes me think that at that place has been some reaction with muriatic acid and vinegar. I've discovered that sparse to wire copper can thus be etched or fifty-fifty dissolved in hydrochloric acid. Seeing that others have made this observation earlier, I need to experiment with other acids in removing calcite in the hope of non damaging the copper or other desirable minerals present. I can't say for sure, just I'one thousand getting the impression that muriatic acid removes the luster of Prehnite, leaving it dull. Some Microcline color appears washed out, though I can't be sure that it happened during crystallization.

8th Oct 2013 sixteen:34 UTC David Von Bargen Manager

A lot of the Up locals utilise sulfamic acid to clean copper. Seems to be a lot gentler than muriatic. It is available in Upwards rockshops.

8th Oct 2013 17:twenty UTC Ronnie Van Dommelen 🌟 Manager

I agree with Rob that etching in HCl can ruin nice copper specimens. I tend not to clean mine at all, though the recipe beneath makes me want to try it...

In the March-Apr 1972 MinRec, Yedlin on Micromounting column, he describes a recipe to avoid the etching. Y'all need a 'non-porous vessel', one part lye (sodium hydroxide), three parts Rochelle salts (potassium sodium tartrate), and xx parts distilled water. Suspend the copper, by a copper wire and dowel, from the top of the container. Shortly the liquid will turn blue. Lift the specimen a few times to check on it. When set, rinse. Take proper condom precautions with the lye.

I have not tried the recipe or know of anyone who has, so I can't comment further. I would beloved to hear if someone does try it.

eighth Oct 2013 17:20 UTC Dan the 2d

Keith,

I utilize a wire brush, attached to a ability drill, seems to have softer bristles.(does not scratch too much) Does a good job, and keeps the polish long enough for articulate blanket. However, if yous take a crystalline / pokey bird nest shape, its hard to get to the interior edges.

I think your correct about the U.P. copper, some of information technology shines slap-up, merely others are stubborn and render to dull colour, time and time once again, Wire brush, seems to fix this. simply its ALOT of work. and makes it hard to get into nooks and crannies.

eighth October 2013 18:54 UTC Mickey Marks

Place the copper in a bathtub and fill up with hot water. Accept a sponge and some soap and scrub the copper until make clean. But first, do not forget to remove his compatible and badge.

eighth Oct 2013 23:21 UTC Scott Sadlocha

I have been using a watergun on some of my copper, merely it is a laborious process that unremarkably takes multiple sessions. Personally, I Detest what HCl does to copper. I learned this the hard way, soaking a overnice Phoenix Mine copper in dilute HCl for merely a piffling while. All defined crystal edges were damaged, and the piece had that typical "burnt" look common to acrid soaked copper, and some of the faces were hackly. After spending time looking at many copper pieces at present, I can usually quite easily see a piece that has been acid soaked.

Anybody is different, but my preference is a natural looking piece, patina and all. To me, bright, shiny copper is unnatural and that is not how I desire my pieces to look. I am nevertheless looking for a good method to clean. I am heading up to the UP in a couple days, and I am going to finish in to some of the shops of there to grab some sulfamic to endeavor information technology on a couple representative pieces. I take institute vinegar to piece of work decently, simply again it restores smoothen. If I take a piece that I absolutely don't want to lose the patina, I have constitute mechanical cleaning the only ways (watergun and picks, soft brushes, etc.)

ninth Oct 2013 01:31 UTC Dan The 2nd

Hullo again,

I take a 10 lbs quartz and copper piece, it took the acid bath, and now is black.

I accept removed most of the black with the wire brush, just there is still a lot I cant get to.

How do I get rid of the rest of the black removed? (Hi powered water washer?) or is it hopeless?

Assistance me out if yous can, I am looking to clear coat presently.

cheers

9th Oct 2013 04:40 UTC Rob Woodside 🌟 Manager

Clear coating will just add together to the impairment of an acrid eaten copper, but it could make a lovely decorator slice. The decorator market is nowhere near as fussy every bit the specimen market.

ninth Oct 2013 thirteen:57 UTC Dan the 2d

Rob,

I hear you lot, but are you saying a blackened, specimen with 0 cleaning volition sell better?(I would tend to largely disagree)

(check out ebay and look at non cleaned versus a dirty and oxidized)

Besides rob, seems that my piece was not damaged by the acid, because of the black coating.

I wish I could show yous my before and afters. Visually my pieces took 20 steps up and kept nigh of its natural look, but with a piddling extra smoothen.

also if you don't clear coat, your going to loose most of the shine. I want people to walk in and say wow, whats that.

9th Oct 2013 fourteen:03 UTC Dan the 2nd

I am re-posting my question,

How-do-you-do again,

I have a 10 lbs quartz and copper slice, it took the acrid bath, and now is black.

I have removed most of the blackness with the wire brush, but in that location is still a lot I cant get to.

How do I get rid of the rest of the black removed? (Hi powered water washer?) or is it hopeless?

Assistance me out if you can, I am looking to clear coat soon.

give thanks you

9th Oct 2013 15:03 UTC Keith A. Peregrine 🌟

Dan,

In cases where the copper turns blackness, I identify it in white vinegar. Ordinarily this removes the black, merely in many cases it turns nighttime again, though non black. I way to minimize this is to place the copper under a rut lamp. The longer water stays in contact with the copper, the greater the dark tarnish. Rarely practice I want to accept a bright copper, just want to betrayal it.

The reason I apply hydrochloric acid is to deliquesce (etch) the calcite. In many cases I have no idea what lies beneath the calcite. This past Copper Land Retreat I ended upward with a great slice containing flecks of argent and copper on top of gemmy epidote. Since at that place was a lot of calcite, I let it sit in the dilute muriatic acid foe over an hour. None of the copper was crystalline, simply flakes. However, I shall seize with teeth the bullet and use some other acid to etch away the calcite in the futurity. If my impatience tin handle it....

9th October 2013 twenty:04 UTC Rob Woodside 🌟 Manager

Dan, the specimen market pays kilobucks for good xls, but aught for an acid blackened piece, no matter how shiny or coated it is. The specimen market is brutal on squeamish untreated Cu specimens with no xls. (Copper skulls excluded) The is too a strong monetary bias for specimens with a mine locality.

27th Mar 2016 06:46 UTC PeterMac

I too have some overnice pieces given to me from a Queensland mine. All of the suggestions have relied on acids of one form or other; from very strong chromic, sulfuric, hydrochloric (Muric), acetic (vinegar), mild citric (love apple). The stronger the acid, the more oxidizing, which can result on blackness copper oxides. The green is residual chlorides from salt, tap water or hydrochloric acids. Significant carbonates can cause blue or dark-green staining, but the conditions are very specific.

A mild acid, free of chlorides, over a longer time is preferred after the "clay" or gange is removed.

I use to use Coke, which is nigh 3 pct phosphoric acid, low in chlorides. Rinse, and leave immersed in water for7 days before exposing to air. If you lot want to keep just for visual purposes. Give a lite spray of Mr Sheen, a mixture of not oxidizing lite oils to reduce later oxidation. (I been told different cokes at present have different formulations... So you may have to experiment)

27th Mar 2016 12:43 UTC Keith A. Peregrine 🌟

With added input from friends and previous results, I have now gone over to Sulfamic acid. Reason being, Muriatic acid volition etch some copper. While taking considerably longer, Sulfamic does non attack the copper. The acid is used to remove calcite which generally covers areas of involvement such as vugs. Acid is also useful in quick cleaning, that is not much more than a dip, rinse, scrub, and soaking in water.

One technique I am using and still experimenting with, is using compressed air to accident off water on a specimen, then placing the specimen nether a heat lamp for ten minutes or so to evaporate off any remaining moisture. This has given me proficient results in preserving the 'bright' luster of copper.

As Rob points out, if y'all know yous have copper crystals, do not use any acrid bathroom!