Help cleaning micro/macro fossils

[Elmo]

I’d like to clean up the micro/macro fossils I’ve been finding so that the the pics will look good. Can they be soaked in vinegar or will that destroy them? 
Here’s an example of what I’m dealing with. 
 

 

[hadrosauridae]

Acid prep is always tricky.  It depends on how the fossil was mineralized, and how much that mineral will react with the acid you use.   It also depends on the matrix.  Not all matrix is compatible with acid prep.  Its difficult to tell from your pictures if you have matrix remaining, or something like limonite which may or may not be bonded to the fossil surface.

 

If youre willing to try, I would start with 10 seconds, then rinse and soak several minutes in distilled water, then brush to see if any matrix comes off.  Look at the fossil under magnification to check for signs of etching.  If no damage is noticed, then try it  30 seconds, rinse, soak, brush, examine.  If you find a point where you see cleaning happening, and no apparent damage, then keep using that cycle timing.  Going for too long can take a great process into a terrible disaster.

 

Just remember, that acid prep is never meant to be a "quick" method, and you need to soak in water for about 10x longer than the acid bath time, to ensure full clearing of acid from the fossil.

 

PS- if this is just matrix you cant get out of the texture of the surface, then air abrasion would be a much better choice. 

Edited April 15 by hadrosauridae

[jpc]

try it first on a fossil that is NOT your favorite.  

 

Just in case.

 

[Elmo]

On 4/15/2024 at 12:45 PM, hadrosauridae said:

Acid prep is always tricky.  It depends on how the fossil was mineralized, and how much that mineral will react with the acid you use.   It also depends on the matrix.  Not all matrix is compatible with acid prep.  Its difficult to tell from your pictures if you have matrix remaining, or something like limonite which may or may not be bonded to the fossil surface.

 

If youre willing to try, I would start with 10 seconds, then rinse and soak several minutes in distilled water, then brush to see if any matrix comes off.  Look at the fossil under magnification to check for signs of etching.  If no damage is noticed, then try it  30 seconds, rinse, soak, brush, examine.  If you find a point where you see cleaning happening, and no apparent damage, then keep using that cycle timing.  Going for too long can take a great process into a terrible disaster.

 

Just remember, that acid prep is never meant to be a "quick" method, and you need to soak in water for about 10x longer than the acid bath time, to ensure full clearing of acid from the fossil.

 

PS- if this is just matrix you cant get out of the texture of the surface, then air abrasion would be a much better choice. 

I’m pulling everything from sand and gravel that I’ve been sifting from local sites on the water. The original matrix it would’ve been in before I recovered it would’ve been clay. I’ll try it out with your recommended method with some of the less that stellar broken fossils. Air abrasion won’t be an option for me right now, I currently reside in an apartment and have limited room for equipment. 
Thank you for the advice, I’m hoping to make these little guys more exciting than they already are. 

[Elmo]

On 4/15/2024 at 2:58 PM, jpc said:

try it first on a fossil that is NOT your favorite.  

 

Just in case.

 

I will start with some broken and chipped ones first. I would’ve overlooked that idea, thank you for pointing it out. 

[sixgill pete]

If the matrix was clay, try soaking them in hot water with dawn dish washing liquid. Then brush them with an old toothbrush.

[MarcoSr]

If not fragile, I would try an Ultrasonic cleaner with water first before vinegar, which can pit and/or discolor some fossils.  I pretty much put all my micro vertebrate fossils in an ultrasonic cleaner to clean them up (salt, dirt, clay, matrix).

 

Marco Sr.

[MarcoSr]

I should have mentioned that micro/macro invertebrate carbonate based fossils will dissolve in vinegar.  Phosphate based vertebrate fossils as stated above could pit or discolor.

 

Marco Sr.

[Coco]

I also wash my shells in an ultrasonic tray, there is no need to put them long in and it peels off the small dirt.

 

Coco

[Elmo]

I tried the vinegar and the dawn cleanings. Both worked fine with no damages to the fossils. It’d be a huge job to brush all of the ones I’ve found so far, so I’m going to take the advice on trying the ultrasonic cleaner. I should have it today and then I can get some pics posted of some of these little beauties posted! Thank you all for your advice. 

[ClearLake]

I will second (or third) the advice on an ultrasonic cleaner.  They generally do a pretty good job, of course depending on what is adhering to the fossils.  But I'm glad you are going to try that route, it is fast and cheap.  If my microfossils are big enough, I but them on a fine mesh fabric and the clay, etc. that falls off slips through leaving just the clean fossil on the fabric for dumping/drying.  If they are really tiny (like off a 40 mesh sieve or smaller) I put them in the ultrasonic cleaner in a small plastic container so I don't have to worry about finding them again in the larger volume of the cleaner.  Good luck and I hope to see some of your results.

[Elmo]

Thank you all for the feedback. The ultrasonic seems to be doing a pretty good job for me. Tidgy’s Dad has started a thread and I’ll be posting pics there!