Thanks for the quick response! A couple follow up questions: -- Is it just steel and aluminum that cause problems? Like, what about a brass brush for cleaning or a brass burnishing wheel? -- A large portion of my normal jeweler's tools are steel -- saw blades, drill bits, burs, files, and forming tools like hammers, punches, dapping pins, etc. Are these also a potential concern? If so, what do I use instead? (lots of head scratching on my side!) -- Is it the titanium itself that's reacting with the steel/aluminum to form oxides or is it the Multi-Etch that's doing the reacting and depositing oxides on the titanium?