Yesterday, prior to walking down the Y-beam manifold from in-chamber to inspect the Cryo baffle and alignment beams, Travis wiped some surfaces.  When he wiped the Gate Valve 1 trough he picked up numerous macroscopic  bits that I'd guess are viton from the o-ring which have shed during cycling.  He also picked up what I will assume is black oxide (seems like what we've seen elsewhere).  These surfaces haven't been touched in many years, so I'm not really surprised at these findings.  See picture below.