Hey all. Can tree sap almost instantly tarnish a blade? I stuck my M9 into a tree a good inch or so (happened to hit right between two pieces of bark). When I pulled it out it had this purplish black tree blood on it. When I rinsed the blade a couple of minutes later it had turned a permanent black in a few spots. Weird. Anyone know anything about this? I don't care that the tip is discolored (it's only gonna get worse from here) but I was just kind of curious.