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john&liz

Cleaning Shell Fossils

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john&liz

Hi everyone....

I have now collected from a number of spots in which I collected shell fossils (Schoharie, NY is the most recent) that could use a little help. Is there any sort of solution I could soak these in (I have quartz crystals from PA that I soaked in oxalic acid) that will dissolve the surrounding limestone but not hurt the fossils (which are preserved in a darker, shale blue gray color)? I realize that this is a bit vague, but my geology is bait weak here. I have a bunch of pieces that are low-grade enough to experiment with... I say this to encourage dialogue. If anyone has collected shell fossils from NY and have soaked them in any type of acid, please let me know.... thanks so much.....

John&Liz

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Rocks Anne

Welcome to the forum. I didn't realize there were shell fossils in Schoharie - I was there a few weeks ago. (Sorry I can't answer your question - I just use a toothbrush and dish soap!

)

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Fossildude19

Hello.

You could try plain old vinegar, and see what that does for you. Make sure when using any acid that you thoroughly rinse with water, to remove any acid, or it will continue to etch the fossils.

Muriatic acid can be used, in varying degrees of dilution, ... but make sure to do it in a well ventilated area, and use any safety precautions recommended on the container.

The problem with the acids, however, are that they tend to destroy the fossils as well, if you are not super careful. :unsure:

Another alternative is to try air abrasive preparation, or invest in an inexpensive rotary tool (they sell them at my local Harbor Freight for 7 or 8 bucks!) and try to prep with a wire brush attachment.

Electric engravers are another alternative. Good old fashioned dental pics work well, but are more time consuming.

Hope this helps.

Regards,

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Indy

Would be interesting in seeing before and after pictures

experimenting using different solutions :)

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Texas-Tunnel Rat

I usally use warm water and brush depending on shell.

Acids are used to break down the tougher stuff.

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erose

Even vinegar should be diluted! But you are on the right track using low grade specimens to test it. Pop the specimen into the solution and watch it at first to make sure it isn't attacking the fossil too vigorously. I've had a few just kind of explode on me when the solution got into deep cracks and the fizzing was too strong. Once you feel confident the acid isn't being too aggressive just set a timer for 10-15 minute intervals. You need to pull them out every so often and scrub away what has been loosened and maybe refresh the solution. Some folks will also wash them in a baking soda solution to neutralize and stop further reaction. I learned this after some of my Texas Cretaceous stuff would grow weird Lavendar crystals after I had used glacial acetic acid. Still don't know what those crystals were.

I have a large collection from Schoharie as well. I have cleaned most of the better brachs with just elbow grease. Start with warm soapy water and a tooth brush. Some of the tougher stuff was removed with a dental pick under a magnifier. And I also sometimes use a brass wire brush wheel on my Dremel. But the great thing about that site is, that if you go back often enough, you eventually find perfect specimens for almost all the species. And there are lots of species to find.

Show us your stuff once it's cleaned up.

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WetlandDad

So...I was going to put together a new post regarding my situation but since this is already a thread. I will lay it out...

I have a C. jeffersonius shell fossil that I just picked up over the weekend that is riddled with barnacles...fairly decent-sized ones at that. I have removed a fair amount of them from the exterior surface. I am however sometimes too strong of a touch for my own good. Which brings me to my query...what should I do to remove most if not all of the barnacles from this specimen WITHOUT causing damage? I am in the works of procuring a Dremel tool, but is there something that might work to help the process along in the meantime?

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Auspex

...what should I do to remove most if not all of the barnacles from this specimen WITHOUT causing damage?...

Oof, this is going to be a tough job! Barnacles cling like, well, barnacles (probably the strongest cement in the natural world), and Miocene fossil shells can be extremely fragile. I think your only real hope is a light touch and world-class patience. There is nothing I can think of that might chemically attack the barnacle attachment without attacking the fossil as well, so physical removal with a light touch seems the only hope.

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Herb

I think the barnacles make the shells more interesting.

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WetlandDad

Well this is where I have stopped with the removal process for now...what do you think?DSCF0016_zpsc654102a.jpg

DSCF0014_zps4c06fbbf.jpg

DSCF0010_zps3117978e.jpg

DSCF0008_zps1402776f.jpg

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Auspex

I think you are patient, and are blessed with a good touch and a steady hand. Your results speak for themselves; I know that I would have made a real mess of it. Well done!

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