Support BladeForums! Paid memberships don't see ads! I have a SAR 5 that I stripped that apparently had the decarb layer left underneath. That stuff is a hairy byatch!!!! I have sanded... and sanded.... and sanded.... and sanded.... until I actually changed the thickness of the blade. I put it up in what I thought was a cool dry place. When I went back a month or so later, it had rusted like nothing I have ever seen. I took it and sanded... and sanded... and sanded some more, until I got worn out. So I put it away again, with the blade well oiled to protect it. About a moth later, I went back and pulled it out to try again. It had rusted again. Biggest mess I've ever seen. At this point, it is still in the "cool, dry" place, still oiled. I've given up on it. Money wasted, but I've got better things to do with my time. That SAR 5 is a great blade shape, IMO. But this particular one is a lost cause. I am beaten. I've stripped a couple others and had no issues with decarb. There was some gray stuff underneath that I kinda smoothed out with sandpaper. No problems with it. I've even stripped SR-101 and left it unprotected, in the same place as the SAR 5, and had no issues with rust. All I can say is, it isn't gray, what I've seen. It looks black, kinda like black mold, but smooth, when I first saw it. Not all over the entire surface, or at least not evenly over the entire surface. But if you strip and see that... you're screwed, IMO. Find a bead blaster and blast the he** out of it.