Cleaning stromatoporoid fossils

[GreatLakesLady]

Hi,

I recently found several small stromatoporoid fossils while hiking in an area of glacial kames, NE Illinois. The fossils I find here have been buried in silt, sand and clay for about a hundred thousand years, and they're sponges! But I love them!

They're entirely silicified, vinegar, clr, and muriatic acid does nothing to them. They aren't in matrix, they're just very, VERY, dirty. I may have to accept some as they are, but was hoping a could do more for the ones that are less porous. Already soaked them in SIO and it did whiten them a bit. First pics are before SIO soak.

I've been reading about oxalic acid, boiling, chlorine bleach, H2O2...not sure if anything else will work besides patience and a toothbrush...

*Also, this is just a hobby so I don't have any equipment other than a dremel, some picks and wire brushes.

 

[DPS Ammonite]

Soak it in hydrogen peroxide (Walmart has the best price) and then brush it with a toothbrush. The bubbles really help to get the dirt out of the nooks.

[Fossildude19]

Also, you might give an ultrasonic jewelry cleaner a try.

They can sometimes loosen the dirt in the nooks and crannies. 

Good luck. 

Regards,

 

[Michelle Truelove]

You also have a nice piece of horn coral fossil, it's the stringy looking one, they kind of look like a mop head!