So is this just a normal coin then? Yes, not silver, but silver colour ..  A 5p dated 2010 is made from cupro-nickel, which can tarnish to a coppery colour, although it is normally streaky.  A picture would probably help if you can get one...  Ok taken a couple of pics.. hope they are clear enough :)I can see now on the picture how uneven the tarnish is..