Hey guys. I bought a carbon Mora, on the recommendation of so many here. It is scary sharp and seems like it'll be a great knife. This morning, I did some carving with it, using green wood, to make a bow for fire making. When I was done, I cleaned it with some soap and water, dried it, and put a little oil on the blade. It's got some rainbow looking spots on it now along the edge. Is this the patina people mention about carbon blades? Is it fine to be there and will it spread, or do I need to do something to maintain it more carefully? Thanks in advance.