Can You Clean Fossils With Acid ?

[matthew textor]

Hi this is Matthew

my question is

can you use acid to clean fossils and what kind should I use ? and does anyone know how to do it correctly ?

 

and thank-you

[Auspex]

That would depend entirely on the mineral composition of the fossil, and of that which you wish to remove.

[Uncle Siphuncle]

I clean echinoids from certain formations with muriatic acid and also use it to etch sutures and blend in scribe marks on ammonites. In addition, I've used the stuff on certain Permian and Pleistocene bones. As said, technique depends on fossil composition and other factors. Do you have a specific application in mind? As a general rule, do a test with your least favorite specimen before committing the best ones. I had to remind a museum of this today when they didn't like the way prep was going on a spectacular echinoid...I gave them a technique using a hammer, brass brush, muriatic acid, and water and they seem to like the result.

[Jack the Collector]

As already stated,but needs to be said again,make sure of the nature of your material before using acid.I too use muratic acid in a well ventilated area.It does the job on most harder materials.Vinegar is also another acid I use.

[Guest N.AL.hunter]

This is copied from an earlier discussion of using acid:

Using acid:

1. Always dilute by adding the acid to the water slowly if you need to dilute it.

2. Work in a well ventilated area.

3. One technique is to place the specimen into a container of water so that it is covered. Then slowly add acid until you just start to see bubbles forming on the specimen. Let that work for a while, allowing that first acid mix to neutralize, then you can add a little more and repeat, or use fresh mixture.

4. Use a scrap specimen for testing first.

5. Place the container where pets can't get to it.

6. Never pour acid mixture into sink without first neutralizing it. It can/will eat your pipes. It is actually best to set it somewhere to evaporate.

7. Wear safety glasses and maybe gloves, but hopefully you are not using acid that is that strong.

[Phoenixflood]

As already stated,but needs to be said again,make sure of the nature of your material before using acid.I too use muratic acid in a well ventilated area.It does the job on most harder materials.Vinegar is also another acid I use.

Vinegar works well with some limestone formations!

[JohnJ]

Keeping in mind the above precautions, I've used a 20 - 25% muriatic acid solution on fossils to remove calcareous deposits. My experience is that muriatic acid tends to "polish" while vinegar will "etch". One small shark tooth several years ago taught me to keep them out of acids. Keeping in mind the advice of others, experience will be your best teacher on various types of fossils.

[Guest solius symbiosus]

Acids can work well, but as others noted ... NEVER ADD WATER TO ACID, it will break a beaker! And, then you will have a real mess.

An HCl prepped trepostomate

[dr heckle]

looking at it from a chemistry point of view check the ph of the fossil before use, if its a strong base avoid acids like the plague