How to clean seashells, sea urchins and coral

how to clean seashells

You’ve spent the entire morning, or day even, combing your beach for local or Florida shells and other ocean goodies. Now that you’ve got a whole bag full, the real work begins. Most people who collect do so with the intention of displaying their prizes for all to see. With that said, you don’t want to decorate that beautiful coffee table or mantle piece with washed out shells do you? To help you out, we complied a short little ‘how to’ all about shells and other ocean treasures. Read below to find out the best ways on how to clean seashells, sea urchins and coral.

Why do seashells lose their color

how to clean sea shellsYou’ve probably noticed that the shells that you find in the ocean start to lose their color and even some of their shine after being on land for a while. This loss of color and shine actually starts when the animal inside it has died. The shells then start to dull further due to both the sun and sand. When waves crash against the shore, they take the seashells with them, thrashing them over and over again against the sand, almost like clothes in a washing machine.

Then the sun further strips the shells of pigmentation, causing the seashells to turn yellow, tan and white. One of the ways you can tell if a seashell can be saved or not is to put it back underwater, either fresh or salt. If you start to see a bit of color, then you know it has a strong chance of turning back into that beauty it once was.

How to clean seashells

how to clean sea shellsSometimes seashells don’t actually lose their color but rater have a build up of calcium on their shells, hiding the color underneath. This calcium is usually white and uneven with bumps and ridges. In order to clean this calcium off you need to:

  • Grab a bowl.
  • Pour in a mixture of cold or room temperature water and bleach (3 parts water, 1 part bleach).
  • Let sit for a few hours, sometimes longer depending on how much of a build up there is.
  • Once a few hours have passed, you can pull one of the seashells out and use a toothpick or paperclip to start tying to take the buildup off.
  • how to clean sea shellsYou can also use an old toothbrush or wire bush and scrub the shell, just make sure to be careful as to not break the seashell if it is a delicate one.
  • Sometimes you’ll need to put the seashell back into the bleach water and let sit for a few more hours.
  • Once they are all clean, rinse off with water to get all of the bleach off.

Make sure to wear gloves with working with bleach and to wear clothes that you don’t mind messing up if there is an accidental spill.

If cleaning cowries, you’ll want to use less bleach. Usually a ratio of 5 parts water to 1 part bleach will work. Cowries have a natural shine to them that can be lost if too much bleach is used in the cleaning process.

How to clean sea urchins

how to clean sea shellsWhen you clean a sea urchin, you’ll have to be extremely careful as these guys are very delicate and will break easily. The steps here are a bit different then those for cleaning seashells as you’ll usually find some meat left in the sea urchin when finding it on the beach.

  • Soak the sea urchins in a bath of warm water (that will end up cooling down to room temperature) for 12 to 24 hours.
  • Take a pair of tweezers and pull out any meat pieces that are willing to come out. If the meat doesn’t want to come out, don’t force it. Sometimes the beak will still be in place, you should be able to pull this out with your fingers or tweezers without any complications.
  • In a large bowl, mix in a ratio of 3 parts water, 1 part bleach and gently place your sea urchins in.
  • how to clean seashellsLeave them for about 20 minutes or so, then check them to see if the meat has all come off, if not put them back in the solution for another 20 minutes.
  • Do this until all the meat is off, sometimes you can pull the remaining pieces off with tweezers as the bleach has loosened them up.
  • Make sure to rinse with cold water to get all of the bleach water off the clean urchins.

Sea urchin shells are known for being very, very delicate and are even more so after bleach is used to clean them. A great way to toughen them up again is to dip them into a mixture of Elmer’s glue and water. If you don’t want to dip them, you can take a brush and apply the solution that way. All you have to do is wait about 10 minutes and you should be good to go!

Sea urchins still have a little bit more work in store for them if you want to both clean and preserve your sea urchins.

How to clean coral

how to clean sea shellsPerhaps the easiest to clean (and the hardest to break) is coral. When you clean coral, you’re actually cleaning off any leftover ‘skin’ that either still dying, or already dead. All you have to do here is put the coral into a solution of bleach water (3 parts water, 1 part bleach) and let sit for a few hours. Then you’ll want to let the coral pieces dry out outside for about a day.

Cleaning with muriatic acid

Some people will use muriatic acid to clean their seashells. Although the acid works like a charm and does an amazing job, it is very dangerous and can easily burn your skin if spilled or splattered. Most who use muriatic acid do so because they want to clean up their shells rather quickly (in 2 seconds) and don’t want to wait a few hours. If you have the time to wait, it’s best to go the safe route and just use bleach water.

Shining up with mineral oil

how to clean sea shellsFor those shells that have just lost their color due to sun and sand exposure, all you’ll have to do is brush on a thin coat of mineral oil. You can buy mineral oil at any food or drug store and it’s usually only a few dollars. When applying mineral oil:

  • Use a small brush or even your hand and smooth on a thin coat.
  • Place shell onto a layer of newspaper to dry for about 2 to 3 hours.
  • Then place seashell in its intended location for all to see!

Usually you’ll only have to rebrush the mineral oil on your seashells once or twice a year. It really all depends on how much you pick up your shells to show all your friends. πŸ™‚



    • Craft glue should work pretty well, you just have to be really careful when pushing the pieces together if the shell is thin. Also, before a sea urchin shell breaks, a good way to strengthen the shell is to apply a mixture of Elmer’s glue and water to the inside of the shell. The glue mixture will coat the shell giving it a second layer of protection.

    • There are two ways, one that’s a lot faster than the other. The fast method is by bleaching the sea urchin, though you’ll want to be very, very careful. What I would recommend is bleach the sea urchin for about 15 minutes, then let the sun do the rest of the bleaching. You could also just let the sun do all of the work and bleach it naturally but this can take several months.

    • On a recent trip to Sanibel (shortly after river was emptied into ocean killing a lot of sea life that was washed onto the shore) I found and brought home some beautiful black branching coral. Do you have any suggestions on how I can preserve this to make it either rock solid or to stay soft? It’s VERY brittle when it drys out so I’ve been soaking it in warm water every few days until I can figure out how to best preserve it.

      Please advise if there is a way to upload or send you a pic since I’m not sure if this is the proper name ‘branching coral’ but feel this is the best way to describe it.

      • I spoke with Rachel. We think you have a “soft coral”. We don’t have any experience with those but I believe they’re usually preserved by drying. If you figure out a good way, let us know.

      • Shannon, Did you ever figure out what to do with your coral? I found a gorgeous piece on Sanibel today and don’t know how to preserve it.

    • Hi Jude!

      It depends. If it’s a bit squishy or raised, then it’s actually a bit of live coral whereas the rest of the coral branch has died. If it is hard to the touch with empty ‘holes’ or ‘borrows’ in it, then it’s left over pigmentation from either the coral polys or the algae that grows along with it.

  1. Hi Rachel, I’ve tried the bleaching and boiling methods, and I have some shells that still smell awfully fishy! ?. Do you have any suggestions as to how I can get the smell out?
    Thank you,

    • I use one part bleach 2-3 parts water I leave my shells, urchines, sand dollars etc in the bleach water for hours, sometimes over night even. Longest was 2 days with some scalloped type shells. After they are cleaned and dried, I may or may not paint a coat of modge podge or acrylic over shell. But nothing I bring into my house after cleaning smells fishy. Try going longer with the bleach if you’re super scent sensitive, try ‘sealing’ the shell smell with a clear top coat. Good luck & keep up the good work!

  2. Many years ago, when we lived in Ecuador, I found a large fan coral on the beach. Now, it has discolored from dust and dirt. I have read the instructions from various sources, as well as yours on cleaning coral. Would a fan coral hold up okay just by using water and bleach?

    • I finally got in touch with Rachel. Below is her reply.

      I don’t have much information on how to clean fan coral, but I would definitely not use bleach. Bleach works on hard corals and shells well because of the tough surface of each. Fan corals on the other hand are flexible and more delicate. I would try cleaning with a hand towel or soft sponge that has been dipped in warm to hot water and go from there. It may take a bit of time, but the fan coral will be much more likely to stay intact.

      • Thanks for the info regarding cleaning my fan coral. I think that before I try her suggestion, I’ll try to gently brush dust with a soft brush.

  3. I collect many shells along Florida beaches. Wash them first to remove sand etc.Then cover in soapy water or bleach and water and let soak. Rinse well, dry and rub down with baby oil to bring back their beautiful natural color. Smells great and looks great for displaying.

  4. I just got back from Sanibel where I had my very first shelling experience. It was EPIC!!!! I found purple sea whip!!!! (Took me a while to figure out what it was called) But now that I know what I have I would like to know how to clean it. I used warm water and a little soap but it still has a fishy smell. It’s not a strong smell but I’m hoping you can help me. How to I properly clean it? Thanks so so so much!!!

    • First off, congrats on an epic shelling experience! We’re very glad to hear that you decided to visit Sanibel, it’s personally one of our favorite Florida islands. The reason you’re smelling that fishy like smell is because the sea whip is still drying out. Depending on where you live it can take up to a few weeks for the smell to really disappear, even if you clean it several times. Do you have an outdoor patio of some sort that’s screened in? If you do, you’ll want to place the sea whip outside and let it finish drying out. Indirect sun is the best if you can, that way it won’t lose all of its color. Then, once it’s all dried out, you can go ahead and gently clean it with warm water and dawn soap. Hope this helps!

    • I would think that’s the best way to keep it orange, as long as your piece of coral is already dried out. If it is still fresh, I would think that the spray paint would end up coming off very quickly.

  5. I put my Nova Scotia sea shells in a bleach water mix and now they are mostly all orange colour! Help!!
    I only soaked them for 2 hours, but I was getting worried bc the ones that were already pretty and white turned orange. What do I do to fix this???

  6. I should have addressed this years ago. I brought back some nice shells from Captiva and Sanibel from 2007. I washed them in soapy water twice, rinsed them off and let them dry on the sink counter. I put them in a container, but they still smell bad. So, now I won’t open the container (clear tupperware). I want to keep the shells. Can I still save them? Will the smell harm me in any way if I try to clean them again? There were no dead animals in these shells even before I washed them. Please help? Thanks.

        • I’d leave the shells out in the open for a couple of days first. If they still smell, use bleach. Wear gloves and keep the bleach off you. Since the bleach tends to dull the sells keep them in the bleach solution for the minimal amount of time it takes to remove the odor.

          • Thanks. I was just thinking. I bring home shells all the time from Myrtle Beach, Folly Beach and Ocean City, MD and they never smelled. I wonder what these did?

          • The animals in the Sanibel shells probably were not dead as long. There were still pieces of organic material in them.

          • Much to my surprise, I decided to open the container and they didn’t smell! I spread them out to look at them and they seemed to be fine. The inside of the container didn’t even smell. I divided them up by size and plan to display them in smaller containers. I am so happy:-)

    • I was at the ocean yesterday collecting seashells for my fish tank and I was wondering is it safe to put it in my fish tank and how should I clean them to put them in there with my fish is this possible.

      • It is safe to put shells in your aquarium as long as they are clean. Make sure there is no organic matter on or in the shells which may rot and pollute the tank. Also, make sure there is no soap or bleach, or any cleaning agent left on the shells.

  7. I have a large piece of blue coral. Now that its full of algae, I want to throw it in dishwasher…toobrittle to scrub off. Do you think d/washer would wkrk, or just stick to bleach? Hesitant about bleach, dont want to lose color. Thank you so much for your help, and all the help you give to others. I know it is very much appreciated πŸ˜‰

    • Hi Renee! If your coral is a piece of soft coral, I would stay away from both the bleach and the dishwasher. Both will end up hurting it. Instead you’ll want to leave your coral under a shady spot outside where it can dry out. That way the algae will flake off once you rinse it in fresh water.

  8. I found some coral that is beautiful burgundy! It’s smells awful, but I don’t want it to lose its color. Is it possible to do that?

  9. Hi there! I found a beautiful, large green sea fan on the beach in Cayman; I had carefully washed it and let it fully dry, and transported it home to WI in a sturdy magazine. It’s still in it,and I’m trying to figure out some way to strengthen it and help preserve the gorgeous green color before I frame it. What are your thoughts on something like a craft spray acrylic (clear), or something along those lines? I’m on a mission!

  10. Hi! Several years ago came across a huge (at least 2’x3′) stunning piece of coral (maybe Acropora millepora?) at a garage sale and fell in love! I bought it and offered it to the local aquarium to use in their tank displays. They turned it down, explaining that they only use fake coral because real coral becomes more brittle over time and disintegrates with the regular cleaning/tank maintenance that they do. It has since become a statement piece in my house. But they were right, it is very brittle, and when bumped or moved, breaks fairly easily. Can I spray it with a top coat of something that won’t discolor over time, but will make it a little more durable? When I dust it, I use a feather duster (and then pick out the little pieces that get caught in the coral) but I’d like to get it tough enough that, when dusting it in the future, I can be confident enough to spray it off with a can of compressed air and not worry about knocking pieces off of it. Thoughts? Thanks in advance!

    • I am very interested in the advice given Colleen since I have a coral (maybe a brain coral) that my husband and I brought back from Hawaii about 47 years ago, and am having some of the same issues she asked about.

  11. I would also like to know if you have any advice about how to treat brain coral, to give it a little shine. I washed and bleached it and now it looks a little flat. Would Mod Podge work to seal it a little?
    Thank you for your advice!

  12. Hi

    A fisherman offered me a piece of orange coral, and he said if i wanted it to stay orange i should let it dry in shade, and then put some matte polish

    what do you advise? and, what about the salt? should i put the coral in fresh water for a few hours?

    thank you πŸ™‚

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