I have a LC Smith Trap grade which was in the white when I bought it. I subsequently had it recolored using charcoal. It came out very nice and I put it away. Over time it started to turn black and now it looks like it was blued. This darkening took several years, but since it was tucked away for an extended period of time, I don't actually know when it turned black. Anyone have this experience , and if so, is it reversible?