How to detect radiation on the metal (coin)? I've got metal coin : http://www.worldpeacecoin.org/
Ruble/dollar, a coin of disarmament with certificate. But, I am very spleeny person, I fear of it's radiance level and I don't know if I can trust it or check it somehow.
That could look weird but my fears feels realistic. I only know that Soviet R-12 (SS-4) nuclear missile is nuclear missile and I'm not sure how do they extract that metal from it? I think that any metal that could be extracted from nuclear missile should be dangerous for my health because of radiance level.
Please tell me if there is a method to check the radiance level of it or why should not I fear it?
 A: There are bigger things one can collect relating to nuclear weapons.  How about this big chunk of metal from the Trinity site in 1945?  http://www.panoramio.com/photo/53676180  Near an engineering school full of people smart at physics, no one is concerned about radiation from this. It wouldn't be on public display if it had any measurable radiation much above background.  
In either case, your coin or Jumbo, it's not the unstable fissile material but part of the (former) container or shell surrounding the dangerous stuff.   Yes, a few particles from the nasty core may have kicked some iron and other atoms into unstable isotopes, but not enough to be a problem.
You get more radiation from flying in a jet at 35000ft or eating a banana, or just standing there since your body naturally contains carbon 14, potassium 40, and other nuclear goodies.
Perhaps someone with more expertise on radiation and its health effects could kindly give more precise numbers than "a banana".   But wikipedia (at the moment) does state this: "In a human body of 70 kg mass, about 4,400 nuclei of 40K decay per second."
Also, just to become familiar with radiation amounts in everyday (and noneveryday) life, see this infographic: http://xkcd.com/radiation/ 
A: 
actual skin of a Soviet R-12 (SS-4) nuclear missile

So it's made from aluminium from the outside of a rocket - a long way from the radioactive end. 
Even assuming a warhead was ever loaded into this missile. I don't know if the USSR routinely kept warheads installed in missiles or fitted them before launch, most soviet missiles were liquid fueled so needed several hours of preparation. 
