Copper is reactive. Can take on all kinds of colors. The red underneath is the actual coin. IDK what the blackish crud is.
I have this 1979 penny that there is black underneath the copper and can really see it on the Reverse side
I don't mean to be cruel, but it's as if no one has ever looked at a coin before. In the first one, it looks like paint. But it could be anything. The second one looks completely normal to me. Coins get crud on them. They get dirty. They react to elements. It's nothing. These are pocket change face value coins. There are billions of them, and millions of them look exactly like this.
many years ago some kid lost a checker from his checkers set so his dad painted a penny black for him.....