Bring Out the Hidden Beauty of Seashells

By Amanda Collett

before and after cleaning and shining seashell

Make your shells shine

Sometimes a quick rinse in soapy water is enough to get your shells ready to display. When they need a little more help, here are some steps to deep clean and polish up your shells.


Some items you might want to have on hand are dishwashing liquid, chlorine bleach, mineral/baby oil, gloves, eye protection, and mask. For difficult-to-clean shells, purchase muriatic acid, tongs, a wire brush, a metal pick, and a glass container. Be sure to measure all ingredients carefully and follow all safety instructions on the packages.

supplies to clean seashells

Basic Cleaning

After bringing my treasures home, I rinse them off in hot, soapy dish water, letting them air dry after cleaning. For many shells, this is all you need to do before displaying them.

Slimy and Smelly Finds

In many cases, rinsing in a 50/50 water and bleach solution for 10 minutes, rinsing with cool or lukewarm tap water, and then letting them dry will solve the problem of shells, sand dollars, and urchins that are coated with algae, smelly, or have a dull color.

In some cases the shells I find are really dirty (e.g., caked with green or black slimy algae) or they have a kiss of death smell (a smell that is so bad it could knock you down). The smell is usually due to a mollusk (animal) dying and then disintegrating inside the shell. It really does smell putrid, but bleach water will solve the problem. You may have to repeat this process several times, but eventually the smell will go away.

Soaking, rinsing, and air drying sand dollars and sea urchins in the same way also brightens and cleans them up. Try to get out as much sand from inside the sand dollars. Some species purposely eat sand to help them anchor themselves to the sea bottom, so they are literally filled with sand.

Full-Strength Bleaching

how to clean seashells

Sometimes, a shell looks black, but it is not algae or scum, but is actually periostracum, the outer-most layer of the shell that forms while the mollusk is still alive. I soak these shells in 100% bleach in a bucket. Check on the shell approximately every other day until it meets your expectations. Trust me—as I have had plenty of experience with this method—the bleach works!

After bleaching is finished, rinse with tap water, then allow the shell to air dry. If you can let it air dry outside in direct sunlight, that is always better.

Drying Dead Animals

If you find a starfish or a seahorse that is dead but still sticky and smelly, place it on a paper plate, cover it completely with regular table salt, and then leave it outside to air dry. Using this process, the starfish or seahorse dries out completely and the smell disappears!

safety when cleaning seashells

Last-Resort Deep Cleaning

If you have a shell that you can’t seem to get as clean as you want, there is one other method I use. However, I only use this method as a last resort.

Following are the steps for cleaning seashells with muriatic acid solution. Muriatic acid can be purchased in the paint department at a hardware store. You will need 2 large glass containers, such as large oversized flower vases, in which to mix the solution and rinse the shell.

  1. Pour ¾ cup of water into the first large glass container, and then add ¼ cup muriatic acid. ALWAYS add the water first followed by the concentrated acid.

  2. Fill the second glass container with water only.

  3. Using metal tongs dip one shell at a time into the acid solution for approximately 3 seconds. You will see “fizzing” as the acid attacks the calcium build-up on the shells. Leaving the shells in longer than 3 seconds can compromise the shell and the color.

  4. Immediately dip the shell into the water to rinse and then place on a towel to dry.

  5. If the shell still has growths or large white calcium buildup on it, softly scrub with a wire brush or use a metal pick. I use the small picks found inside dental kits and they work well.

When you are happy with how your shell looks, give it a final rinse in tap water and let it air dry.

cleaning seashells before and after

When you are finished with the acid, dispose of it properly, as it is dangerous and corrosive. Fill your second rinsing container with a solution of tap water and baking soda or lime. Slowly add a small amount of the muriatic solution. Alternate adding baking soda and muriatic solution until there is no “fizzing.” Once the fizzing ceases, the mixture should be safe for disposal. DO NOT dump muriatic acid down your drain or into the sewer system without neutralizing it first.

Be sure to read all safety directions before using muriatic acid. It is extremely necessary to follow all recommended safety precautions while using this type of solution.

Bringing Back the Shine

In order to get a shell’s original shine back, I brush or rub on a thin coat of mineral oil, and it looks amazingly beautiful again.

protect sand dollars

Protecting Fragile Pieces

The best method I have found for protecting clean, dry sand dollars and urchins is to treat them with a 50/50 water and white glue solution. Use a small paint brush to coat the sand dollars or urchins with the glue mixture. If you have a lot of them, you can let them soak in the mixture overnight. Place them on wax paper to dry in the sun. When they are dry, turn them over and coat the other side and allow to dry.

Learn more about seashells

nature and history of seashells and collecting

Learn more about identifying shells, the history of seashell collecting, great shelling beaches, and the lives of the animals who make the shells we find on the beach. Articles ›

No live shelling: Be sure shells are empty and sand dollars, sea stars, and sea urchins are no longer alive before you bring them home.

For more information on finding, identifying, cleaning, and creating art with shells, pick up a copy of Amanda’s book, My Way of Shelling, by contacting her on Facebook or Instagram @amandas_oceantreasure or via email at

This article appeared in the Beachcombing Magazine July/August 2020 issue.

No live shelling: Be sure shells are empty and sand dollars, sea stars, and sea urchins are no longer alive before you bring them home.


There is a safe HDL now out there. Totally safe unlike Muratic acid.

Sherry August 15, 2023

Cleaning shells. I lived in Central Florida about a couple of hours to Ft. Meyers.
Used to go shelling on Sanibel Island. This was back in early 80’s. Was a small shop on island that sold shells and such for souvenirs.
I picked up a book that I think was labeled “Shelling on Sanibel Island”.
First time I heard the phrase of doing the Sanibel Shuffle. In this small book was a section that said how to clean the calcium off the shells. Can’t remember the exact amount of solution but was ratio of 3 to 1 drops of baby oil and lighter fluid. Mix in small dish/bowl and use a small brush that the author suggested a brush from a sewing machine. I used and all the shells I did turned out great and color was restored. I don’t recall not being able to remove the calcium with the formula.
I still have some of the shells all these years later and still look good.

Deborah Coblentz June 15, 2023

Thank you so much for this information.

Diana Catindig May 22, 2023

Shells from salt water is there anything to use to put in place of the muraitic acic and how ro shine and keep them shiny

Juanita Long February 05, 2023

Please take the muriatic acid solution outside or to a properly ventilated area. Acid fumes will do instant damage if inhaled at that concentration. If it’s bubbling or sizzling, there are fumes.

Dr. Benway November 17, 2022

I suggest that you neutralize the muriatic acid with baking soda before disposal

Dena R Russeau July 07, 2022

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