A friend of mine gave me five coins encased in what seemed like cement. After many soakings in various solutions (things like adhesive remover, OOPS, Acetone, paint thinner, Brasso, Fantastic, and other stuff I had hanging around the house - never in combination with each other), picking with a dental tool, and brushing with a suede brush, I got them to a point where I could see designs. They are shown below. Now that you can see them, can anyone identify them? I am a Federal Reserve Note error collector so these are WAAAY out of my league. Any help would be appreciated. Especially with the fourth one which is barely visible.