Hello Thank You for the Great Advice. I think I try the Brown Marker or Brown Shoe Polish. Very Helpful.Those buttons invariably do that due to the wear on all the exposed edges. A temporary solution would be a wipe over with some brown boot polish then buff or run a brown marker pen over the edges. A somewhat more permanent fix would be to use a brown leather dye but with all these the wear will usually occur again. I have tended to replace badly worn leather buttons though but looks like yours are not at that stage.