(Original Forum Question : I have just returned from a beach vacation where I collected many shells. How do I get the bad odor out of them)
If the whole animal is still in the shell it must be removed. This is usually accomplished by either boiling or freezing/thawing the specimen, followed by shaking the animal out, or picking it out with a thin sharp tool. Once the major portion of the soft tissues have been removed, the shell can be completely cleaned and deodorized by soaking in bleach (1 part Chlorox or other liquid laundry bleach to 9 parts water). For very dirty shells with a lot of heavy external matter, dilution can be 1 to 5. Lower gastropod (snail-type) shells into the bleach spire down, so the solution can run into the shell and fill the interior. Allow to soak for an hour to overnight, then flush under a strong stream of fresh water.
(Answer by M. Paul Monfils via the Forum)
(I recently returned from a trip to Cancun, and we were given a Seafan by a man who wanted to thank us for showing him this great spot to find shells. We brought all of our lovely shells home and they are scattered throughout my house to remind me of the wonderful turquoise water and coral sand.The Seafan, on the other hand, is sitting outside in 30-40 degree temperatures due to it having a very strong odor. It has been outside for a month now and it still stinks! Does anyone have any ideas on what to do with this otherwise lovely creature?)
The ideal treatment would be to soak the specimen in formalin (formaldehyde solution) for a couple of days, followed by soaking in alcohol, followed by drying. However, in the event you don't have access to formalin, or are not familiar with its use, just soaking in alcohol should help. "Rubbing alcohol" from the pharmacy is suitable. Sometimes they have rubbing alcohol that is 90% concentration. If so, that would be better than the 70% solution more often seen. Depending on the size of the seafan, you will need some sort of large flat container wide enough to allow the specimen to lie flat, and deep enough to hold sufficient alcohol to cover the specimen. If the specimen floats, put a weight on it to keep it submerged. After 24 hours or more in the alcohol you should discard the alcohol and cover the specimen with fresh alcohol for at least another 24 hours. It can stay in either alcohol solution much longer than 24 hours without harm if necessary. 24 hours is the minimum. However, if the alcohol begins to take on the color of the seafan (if the seafan is red for example, and the alcohol starts turning pink) that indicates that some of the pigment of the seafan is dissolving out. In that case, limit it to 24 hours in each alcohol, to avoid losing any more color than necessary. Seafans often lose much of their color anyway, once dried. Since yours is currently "refrigerated" it probably hasn't lost much color yet. Some people color them after they are dried by dying or spray paint of some kind. Once the specimen has been soaked in both alcohol solutions, just take it out and let it dry. If there is any residual odor while drying, it should be gone once the spcimen is completely dried. Some folks spray seafans with lacquer or some sort of plastic spray to seal them and strenghthen them. This however imparts an unnatural gloss to the specimen. To seal and strengthen it without creating a glossy effect, there are a couple of methods. One is a matte finish spray that can be purchased at an art supply store. It is used, for example, to spray on charcoal drawings to "fix" them so the charcoal won't smudge when the drawing is handled. The other option is a mix of white glue like Elmer's Glue-All or Sobo Glue in water, about 1 part glue to 9 parts water. Spray or brush it on, shake off the excess, and let it dry. These coatings dry invisible but still seal the specimen against moisture and strengthen it.
One last consideration – if your specimen has a large "hold fast" attached at the base (like a "root ball" on a plant), that may be the source of most of the smell. Such a structure may contain many small mollusks, crustaceans, marine worms, and other organisms which collectively can produce quite an odor when dead. If that is the case, you still may be able to squelch the odor by soaking, though in this case longer soaking would be needed and formalin might be necessary. Alternatively, much of the odor may be eliminated by simply getting rid of the holdfast.
Note: Smells can be removed from shells using bleach, but don't try this on a seafan. It will destroy it. Good luck.
(Answer by M. Paul Monfils via the Forum)