It’s important to remember that Obsidian doesn’t remove oxidation but it can protect it from returning. HOWEVER, I have found that it is never really safe to go smoking in direct sunlight with Charatons or Upshalls. Any of those stems that have aged or been previously restored even with Obsidian Oil will begin to oxidize. For that reason, I am outfitting my Charatan pipes with newer stems just for smoking. I’ll keep the original stems in a drawer. I’ve done this with other pipes for the same reason. Briarworks can make a comfort stem with the CS on the stem. It looks original.