I have two particular cues that have some shaft discoloring but I'm not sure where from. One playing cue has tiny dark lines where the grain is however it's underneath the clear coat, on the joint end of the shaft. I also have another cue that's more of a collectors cue that has never been played, however on the shaft there is a place about 2 by .5 inches oval that looks like a normal shaft that has been played with for about 2 weeks. This oval area has just the tiniest amount of green in the grain (like chalk). I don't know how this discoloration could have gotten there. Both cues have been stored vertically in either Whitten or Guiseppe cases. I take the collectors out on occasion to show off. Any ideas why either would discolor?