Clorox bleach helps a great deal with the removal of calcareous deposits. A lot of these deposits result from coralline algae growth, which is composed of both calcium and organic components. The bleach will dissolve the organic material, which helps to weaken the deposits, making them more porous, and renders them easier to remove.
The concentration of Clorox I use depends on the shell, but I've had no problems with 1/3 or 1/2 strength solution when dipping Conus, Cymantiums, Murexes, and similar shells. I've even kept particularly crusty shells in the solution for several weeks with no apparent ill effect. I would not advise placing any especially glossy or thin-shelled specimens in bleach for more than a few hours, however.
After the dip, drying the shell thoroughly helps to embrittle the deposits, making them much easier to chip off.
Another advantage of bleach is that it helps to dramatically whiten deposits. This makes it easier to tell the difference between shell features and fouling growth for darker-colored shells, thus reducing the chance of accidentally chipping off shell material.
Aloha,
Dave Lum
From: "Monfils, Paul" <[log in to unmask]>
Reply-To: Conchologists List <[log in to unmask]>
To: [log in to unmask]
Subject: Re: cleaning question
Date: Mon, 19 Sep 2005 15:31:55 -0400
>The problem with removing calcareous deposits from shells is that the
>deposits are usually composed of the same material, or at least very similar
>material, as the shell. Therefore you can't use chemical methods to
>dissolve the deposits (as you can with non-calcareous deposits and
>periostracum) because any chemical that will dissolve calcareous deposits
>will also dissolve the shell. So you have to resort to physical means of
>removal such as scaping, picking, brushing and sonicating (use of an
>ultrasonic cleaner). My initial assault on calcareous deposits is usually
>with a wire brush. For substantial deposits on sturdy shells I use a 3 inch
>rotary wire brush mounted in my electric drill. For lighter deposits on
>smaller, more delicate shells I use a 1 inch rotary wire brush in a Dremel
>tool. This often completely removes the deposits, or at least removes most
>of the material so that there isn't too much left to pick off with a needle
>or other sharp instrument. The bristles of the wire brushes should be steel.
>They sell softer wire brushes made of brass or other metals, but these do
>not cut through the deposits nearly as well, and they may leave a metallic
>deposit on the shell.
>
> > ----------
> > From: Conchologists List on behalf of David Kirsh
> > Reply To: Conchologists List
> > Sent: Sunday, August 21, 2005 9:28 PM
> > To: [log in to unmask]
> > Subject: cleaning question
> >
> > OK, I know we probably covered this recently but I can't find it in the
> > archives.
> >
> > How do I remove calcareous algae from an outer lip without damaging it?
> >
> > Thanks in advance,
> >
> > David Kirsh
> >
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