I've got these two G-10 handled knives;a C19 and a Benchmade AFCK. Both are NIB,never carried/used,haven't been displayed,etc. But both their handles have turned a sliver/grey color. What's weird is I have a second AFCK of the same model(prolly same year as well) that has been carried and used,but the handles are perfect black. Anyone know why this happens? Any way of fixing it? Thought about using Armor All for a second,but don't want the handles to be slippery.