Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Muriatic acid for cleaning sea shells
Q. I was told I could clean the film off of sea shells with muric acid. I have had no luck in finding this product. Hardware stores try to sell me muriatic acid, or tell me there is no such thing. In which "field" do I search for this item? Someone said maybe jewelers or construction.
Any info appreciated, Aloha!
Betty WestWest Art - Kaunakakai, Hawaii, U.S.A
2002
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A. Hi Betty. I've never heard of muric acid and am sure that it's just a corruption of the spelling for muriatic acid ⇦this on eBay or Amazon [affil links] . I don't know anything about seashell cleaning and am not implying that muriatic acid is appropriate for cleaning the film off of them. But if it is, you probably need to dilute it substantially to not destroy them. Good luck.  Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey 2002 A. Muriatic is the proper term for the acid you are looking for. The word "muric" is a mispronunciation. Yes, muriatic acid will remove the film from seashells - but also will consume the shell in the process. Muriatic acid (chemical symbol HCl) is an excellent dissolver of calcium - the major component of seashells. A commercial product available in stores for removing calcium, lime, and rust stains is called C-L-R ⇦this on eBay or Amazon [affil links] (see the similarity?). I would try a good household cleaner before trying something as aggressive as muriatic acid (also called hydrochloric acid). Dan Brewerchemical process supplier - Gurnee, Illinois 2002 A. Having never heard of Muric Acid, I did a quick web search in case my decades in chemistry and metallurgy had somehow missed such a substance. Each of the hundred or so hits that were sensible, all described situations where the substance being discussed was assuredly Muriatic Acid (a common name for slightly impure Hydrochloric Acid). I would expect this would dissolve the seashells, with much fizzing, as well as any film or deposit that was on the shells.  Bill Reynolds [deceased] consultant metallurgist - Ballarat, Victoria, Australia We sadly relate the news that Bill passed away on Jan. 29, 2010. 2002 A. They are probably referring to Muriatic Acid. Dilute Muriatic Acid is usually available in paint stores since it is frequently used to condition concrete for painting. Gene Packmanprocess supplier - Great Neck, New York 2002 |
A. Hi Betty!
I think that someone meant to say muriatic and not muric.
For more info on this acid, have a gander in the archives at # 12044 (asking about hydrochloric acid formula). There's a lot of extraneous info on those responses which isn't relevant but some useful info, too.... And if you are a dawg lover, you'd like it.
Or go and have a look at 13393 ... where there is a far better answer than mine ... but, you did ask about an acid, didn't you!
Expert advice on chemicals from a sea shell collector! Cheers!
Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).
2002
A. Many years ago my parents owned what was then called a "produce station" where we bought various items from local farmers and the re-sold them to a wholesaler. In the process we bought cream from dairy farmers. To test for butterfat content muriatic acid was used. Believe me you don't want to use it to clean sea shells. It is super corrosive and dangerous to your health.
After many years of scuba diving and much help from experienced shell collectors a much better alternative is COMMON HOUSEHOLD BLEACH
⇦ bleach/sodium hypochlorite in bulk on
eBay
or
Amazon [affil links]
. Take a large metal or porcelain container and mix up a diluted batch of household bleach and plain water. Submerge your shells in this solution for approximately a week. At the end of this time you should be able to take a wooden toothpick and easily remove the calcium deposits; they will be like putty in texture! Large, obviously older deposits, may have to be resoaked in this solution. To collect shells without holes (made to remove the contents of the shell) place the intact shell on the ground (meat side down) mound dirt up around the edges and leave it there for a month or two; summer time is best. Ants will eat the meat out of the inside during this period; then place it in your bleach solution for a week or so to remove any of the residue and the odor. Wallah....you have a trophy.
(Remember: In most places in the world it is illegal to collect these shells. You have to experiment with the bleach solution to get the correct dilution.)
Marketing Consulting - Humboldt, Kansas USA
2007
A. If you're looking for muriatic acid go to a pool supply store they carry it there. Lupe
Lupe Pedraza- Pinetop, Arizona
March 2, 2011
June 7, 2015
Q. I have poured 6 cups or so into a plastic flower pot inside another plastic flower pot to be safe. I cleaned some sea shells with it. With metal thongs, I dunked them in water for 3 seconds, then dunked them in water, and they are colorful and pretty again. I saw this on a video on Pinterest and Facebook.
I put tin foil over the top of the acid pot for the night (in a back hall with an open window, good ventilation). In the morning I saw that the fumes had eaten a big hole through the foil. Later that day the foil was almost gone. The next day the acid has eaten through the first plastic pot. That is today and I am concerned about when it will eat through the next one, and then what? It will be in the back hall on the floor.
!! Please help !!
What do I do? How much of what do I add to it to keep it from spilling onto the floor of our rental house?
What type pf container should I use in the future, as I will be dipping more shells, since I m moving to the beach.
!! Please advise !!
Many thanks.
Eek.
Jen
- Crozet, Virginia, USA
A. Hi Jen. Not all plastics are acid resistant. Nylon, for example, isn't.
Glass is acid resistant, as are several types of plastic, including polyethylene, polypropylene, and PVC (vinyl). Maybe you can find recycling codes that will help you embossed into the containers. Look for numbers 2 through 5, and they'll probably be okay. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 2015
A. I have cleaned thousands of seashells through the years. I would certainly NOT recommend muriatic acid. This is much too harsh and DANGEROUS unless you know what you are doing. It will severely etch the shells.
Common household bleach works fine and is much safer. I usually use a blend of 50% bleach and 50% water.
After bleaching to remove incrustations, etc. and drying, you can put a light coating of mineral oil, baby oil, vaseline, etc on the shell to bring out the color if it is an old beach shell. I usually dilute the oil with some paint thinner -- maybe 50/50.
Lee Kremer
Stellar Solutions, Inc.
McHenry, Illinois
June 12, 2015
Q. Hi. I have my muriatic acid in a large canning jar. It's not wide enough to do my larger shells but that's okay. I've been cleaning my shells this way for a couple of weeks. Now my concern is how to dispose of it because it has dwindled down to 2" of acid. I heard I could add baking soda to it ... let it do its 'thing', then flush it down the drain. Can anyone confirm this? Good luck with your shells btw (don't put the olive shells in the acid). Get it out of the plastic pot. Canning jar in large is 1.98 at Walmart. worth it. Carol
Carol Jones- Punta Gorda, Florida
March 26, 2017
A. Hi Carol. Dilute it as much as practical by adding some water, but not beyond about the 2/3's mark on your pot. (You're supposed to "add acid to water", not "add water to acid", due to the danger of overheating, but on a small amount of exhausted acid it will probably be okay -- just be sure you're wearing goggles ⇦this on eBay or Amazon [affil links] in case).
The reason you want the pot only 2/3 full is that it will foam madly when you add the baking soda [in bulk on eBay or Amazon [affil links] . Add just a tiny bit and stir. Add a little more and stir. As you keep adding baking soda, you'll see that the reaction is slowing down as the acid gets weaker. You'll reach a point where the foaming stops and you have a small excess of baking soda which you'll see settle when you stop stirring. It's neutralized and okay to flush. Businesses are restricted on this waste treatment stuff, but a careful individual hobbyist probably won't get in trouble as long as they're careful not to hurt themself :-)
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2017
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