Copper. The colors can vary wildly and the cleaning (your coin) adds even another dimension to the color. I collect what is called woodies - where the alloy did not get properly mixed. One area will be high in tin/inc while another will have virtually none. Just look at the color variations they show.
Plated. Could be silverplated, nickel plated, chrome plated, doesn't matter it is all post mint damage and has no added value above face.
It's a valuable error since it is obviously a 1935 but they used a 1945 by mistake. Worth about $240,000. Kidding.
Welcome to Coin Talk. You can find out a general value for your coin by going to NumisMedia, NGC’s US Coin Price Guide or CONECA’s Variety Vista websites. As a new member, you need to also go to Wexler’s doubleddie.com site and read his sections on the die making process and worthless doubling. By doing this you will pull yourself up by your own bootstraps and launch yourself light years forward in this hobby. Welcome, again, and good luck!…Spark
First, welcome to the neighborhood, Jodie! As others have suggested, you should start your own thread since this thread is about 8 years old, and be sure to include clear photos of both sides of the coin. Nobody can be expected to give you an estimate on condition or value without photos. ~ Chris
