Confused with this tar and patina covered penny???

[patinapetunia]

I am an amateur (started about a week and a half ago) to the whole treasure hunting thing but I do know that this penny I have is one stubborn penny. I recently ( about a week ago) went to the beach for treasure hunting and found this penny stuck in the tar. As you can tell, you can't even see the penny's imprints. I have tried soaking it in vinegar and salt for one day, soaking it in acetone for one day, Coca Cola for another day, I tried scrubbing it with ketchup and a toothbrush, and tried erasing it with an eraser. I've researched this over and over but can't find an explanation to why I can't get the tar or patina off and why it look like it does. Any ideas on why this penny looks like this and how I can clean it?

 

[patinapetunia]

I've recently been digging in an area where the Chumash used to live an have found this arrowhead looking shape. I cannot tell if it is an arrowhead as I am an amateur. The object looks too sharp to not be manmade yet it has no chip marks. Does anyone know if this is an arrowhead and if so what material it is and when it was made?

 

[Piedmontartifacts]

I’m not sure about the penny maybe goof off or even gas if it’s actually tar. But I don’t think the rock is an arrowhead but may be a tool of doom sort. Good luck out there!

 

[chuck ky]

The penny looks like its a modern zinc so its not worth the time or money to try to clean it up. Just put in in a roll with the rest of your pennies.

 

[patinapetunia]

Thank you!

 

[GeorgeinSC]

Modern pennies are 97.5 percent zinc with 2.5 percent copper coating. zinc corrodes rapidly when exposed to mineralized soil and even faster at a salt water beach. Those that have been lost for a period of time are totally worthless.