You can clean off the green. I use Colinite #850 Metal Wax or Flitz. Good stuff for metal, but be aware that the pitting in the chrome on those fittings cannot be polished away. That is actual holes or openings in the chrome covering of the bronze fitting. The bronze is a very good stable metal for that type of fitting and will last longer than you do, but it is plated with chrome to make it look pretty. Without occasional polishing the salt will eventually get to the plating and expose the underlying bronze, which develops a green patina when exposed to the elements. The Colinite or Flitz will make it look much better but not like new. The fittings usefulness is not compromised however.