The first thing to determine is the type of metal. Do you have any of the following available to you: 1. muriatic acid (obtained at lowe's for four dollars,) 2. A soldering iron. 3. a pan, aluminum foil, and baking soda.
if we can identify the metal first I feel it would greatly aid in the identification. But we must start there...
A lot of this looks like trim for stuff inside the house, e.g., what appears to be an escutcheon in your first picture. The first thing you can do is turn the light on and turn off the flash on your camera (if either of those weren't the case before). The color is blunted in your images and it's extremely difficult to tell what I'm looking at. Any time you have metal that is non-ferrous and non-jewelry, the go-to material is going to be brass or bronze. Having said that, get some better pictures, and let us know what color you perceive the oxidation/base metal as. Take a sharp object and scratch an inconspicuous area and tell us whether the metal underneath looks silverish, goldish, purplish, etc. All of it looks like brass to me, except for one piece in the last picture which might be straight up copper.