A. Michael Dresdner: "Any film forming finish will work, and all are basically skin friendly, but that does not mean someone won't react to it. People are allergic or sensitive to all types of things. My wife can only wear gold earrings, not stainless or silver, both of which are usually considered skin-friendly.

"Considering the situation, I would probably choose either an oil-based polyurethane, or cyanoacrylate, both of which are very stable, and highly resistant to both acids and alkalines."

A. Rob Johnstone: "Wow, I have never considered such a question before. And it will come as no surpise that I haven't a clue what the correct answer is. Two of my three children have experimented with piercings and tatoos & I have not. If you will forgive a bit of fatherly advice (one of my three kids has taken it to heart): Getting a tatoo is like having platform shoes sewn to your feet. As someone who came of age in the 70s, this presents a vibrant mental image. Moral of that silly story? Don't do anything irreversable to your body that you will regret later. Good luck!"