Need help with a button

[Captain Caveman]

I found this 2 piece button on a property built in 1860. The back was broken off when I dug it, and I was only able to retrieve half of it. I've been trying to clean the front of it by leaving it soaking it soap water and then scraping it with a toothpick, but it doesn't seem to be working very well. I notice that it has gold glint in areas. I'd like some help on how to clean it. Also, any ideas on what it is? I know nothing about buttons beyond being able to recognize an eagle!

-edit - the little white looking spots are gold glint.