Hrrm, on one hand the Smelter should not be too much of a Universal Recycler, which is why it does not work outside of the Crucible or Shredder, on the other hand Coins are dead simple apart from their implementation making them too complicated for the Smelters Recipe System.
I would suggest using the Shredder first and then smelt it, because I dont know if that could be easy to work with.