How should it be done?
It’s a question we get asked all the time, “How do I clean my gold?” Sometimes those nuggets come of the ground bright and shiny, other times we don’t get so lucky. Quite often they are concealed beneath a layer of mud, muck, clay, ironstone, caliche, grit, grime, and all the other treats Mother Nature has at her disposal. In most cases this crud detracts from the natural beauty of the gold and must be removed, but what is the safest way? Do we risk dipping our newly found treasure in a dangerous acid to bubble & fizz off the impurities, or do we chance something even worse; using our wife’s toothbrush to scrub dirt out of the cracks & crevices??? We posed this question to the members of the Arizona Outback Prospecting Forum, and these were some of the replies:
Well, I clean my solid or mostly solid gold nuggets, with a tooth brush in dawn dish soap. After scrubbing in that, I put them in a bottle with a salt and vinegar solution and shake it up for a few minutes. Cleans them up really nice. For quartz specimens I use the same thing followed by an over night dip in glass etching solution. Here’s how good it makes the gold and quartz look. Grubstake Ps I forgot, if you get one that has a lot of rust, you can use navel jelly. Just leave it in overnight
I used to use Hydrofluoric Acid until I had the nails of three fingers on the right hand ripped off by the local medical staff. This stuff can be LETHAL unless properly treated by trained medical staff. It doesn’t wash off in water. These days I use soap, water, brushes - dishwashing liquid, some times a little bleach or other strong cleaning solutions .... but NEVER HF Acid.
I've had pretty good luck with foaming Ammonia and lightly shaking in a bottle. Except for this last time. One of my little nuggets must of been held together with that mud! I now have 3 little ones and a bunch of flakes.
For cleaning nuggets I use a Jewelers Ultrasonic cleaner with warm water and a small amount (spoonful) of Jewelry cleaner. In a few minutes it's a beautiful Gold nugget without being too bright like some I've seen that were treated with acid. Same thing for specimen-type gold, except I go over it with a toothbrush first to get out any heavy encrustations in the nooks and crannies. If it is REAL bad, I will rarely use acid.
I prefer to keep my gold pretty much as I find it. If I want to clean it, I have found soaking in dish soap, rinsing and then soaking in white vinegar to be very effective...
A good way to clean off the red staining on a lot of gold here in Australia is to use Oxalic acid. Oxalic comes in crystal form and has to be diluted in warm water before it can be used. The best way is to get a Pyrex beaker or jug, place on a low gas flame in a well ventilated area and gently simmer for a few hours. This method works extremely well on white quartz specimen gold, but is no where near as aggressive as other acids. I have also used Drano (for unblocking drains), just make sure the container can handle a fair bit of heat because once that stuff hits water it really goes to town in a big way, Drano will rip off a lot of the loose dirt but is not so good on anything hard. If you have a problem with iron stone the best acid is Hydrochloric, Hydrochloric will remove iron very quickly but you need to refresh the acid at least twice a day as well as scrubbing the nuggets individually with a tooth brush before returning to the acid.
I used to use diluted nitric acid, which during cleaning actually causes it to appear slightly tarnished, then I diluted and poured off the nitric solution. Next step was to dry off the nuggets then I heated them up using an enamel camping coffee cup. I just set it on the stove burner and set it on high for about 15 minutes. They come out very shiny. Nowadays, I don't clean them unless you just can't tell their nuggets. I like retaining the personality of the nugget, just the way I found them.
I clean my gold by using hardened and highly polished blend of balls, pins, ball cones and angle cuts of stainless steel. I put about one oz. of the polishing media in a small plastic bottle along with some dish soap and water and add dirty gold nuggets. Shake the bottle for 10 minutes. It will not remove all the stains from the Quartz but will leave the gold nice and shiny without removing any Gold or Quartz. I have cleaned small gold from dry washing and the results are amazing. Lime away can be used instead of soap for removing large amonts of caliche. I purchased the polishing media from Kingsley North Inc. Toll free #1-800- 338-9280, or www.kingslynorth.com. A one lb. package costs 16.95 and will last a life time for you and a dozen friends.
A good toothbrush and dishwashing detergent can give really good results on most gold nuggets. If ironstone is a problem to you I have found that to get rid of this I soak the nugget in hydrochloric acid for a couple of days and then wash them with a toothbrush and dishwashing detergent. (The ironstone 'turns' into a clay-like substance). They come up a treat, but common sense is needed when using any sort of acid (the hydrochloric acid is the stuff bricklayers use to wash down brick walls). I keep away from the other acid - the Hydrofluoric Acid as that stuff is mean and nasty, sure it will get rid of quartz but you can destroy a very nice specimen. Enjoy the specimen for what it is - something really special.
Cleaning gold for maximum value and to enhance it's beauty will vary depending on host rock, staining and other types of “gack” that attaches to it . Many desert areas have caliche or a lime carbonate build up which is easily removed with Limeaway or a mild muratic acid ( pool acid) mix. If there is iron staining a quick cleaning in an ultrasonic with green wonder jewelry cleaner works great. It will also remove some of the surface staining in quartz. There is a mineral dealer out of San Diego (Kristallie) who X-rays their larger specimens and waxes one end to make a stand and Hydroflorics the rest of the quartz off. Making some very impressive museum type display pieces. That process really depends on the nature of the gold contained within. If the host rock is limonite or limestone a simple weak pool acid solution and cook to the desired results will work. Always after using acid neutralize the item with baking soda and water until it doesn't fizz anymore. I have always been fond of the Aussie ironstone and gold species. They are mostly ruined by Aussie prospectors yet they command high prices at most gold shows. Once any acid is used for etching the piece will not be anything that is easily handled. I have ruined many pieces by handling them once etched watching them crumble in my hands. This year at the Gem show there was a small cube crystal of gold aprox. 1/2 inch by 1/2 inch (I'm sure it was etched out of rock) that Krystallie turned down offers at $100,000 !! Yet I can't believe some people still use a dollie-pot ??? Well Here's some pix of posters and post cards I got on my wall. These pieces are spectacular and most are beyond our affordability!! Yet they all started out as hunks of rock.
I just use a toothbrush and tooth paste. You know I once met a person in France
who had a Mineral shop and saw this beautiful gold specimen. He showed it to me
and I asked him, if it had been in acid, he said yes. So, I took some of my species out and showed it to him, not as shiny but more natural. He looked at them, and then at me, and said that’s what customers want now. They must remain as natural, to much outside intervention on species sure makes them look nice, but I think they loose there charm and history. I mean look at it, they probably took million of years to be the way we find them, and we can change there appearance in a few hours or day's. No, personally I leave mine the way I found them; ugly or beautiful.
I have cleaned 2 of mine the old fashioned way. I put it in my mouth and sucked the crud off.
Materials: A wet mouth and moist tongue plus 1 dirty nugget.
Steps: 1) Place dirty nugget in your mouth 2) Roll in your mouth and moisten 3) Suck and lick the grime off 4) Spit the crud (not the nugget) out on the ground.
Safety Precautions: Make sure it’s a gold nugget and not a rabbit or deer nugget.
Works great on the ones I cleaned!