Some times that attractive greenish color, at least to me it is attractive, of the metal may be the result of having been originally stored with cosomoline on the metal and which chemicals have a habit of tinting a light grayish parkerized metal to a greenish tint after awhile. Be careful, as using a degreaser or a metal cleaner, such as Acetone on the metal, will instantly return the metal back to that light grayish color it was born with. Ask me about how I know. Using a gun oil should be ok to clean that grease. Ray
Thanks and I don't plan on using anything on it except oil and never have or had to. I have always tried to keep them oiled, especially since I don't take my guns out often.