OK, so I have a reply from the guys at Eagle One, quote:
Thank you for your question. The Nevr Dull product is a very unique product with the wadding material that contains a special polishing substance that is solely recommended for metals, such as brass, copper, aluminum, etc.. Paint finishes in general, (clearcoat, polyurethane, lacquer, etc.) is something that we do not recommend this product for, simply due to the abrasiveness of the product. The wadding material in the Nevr Dull still contains a lot of the original cotton seeds, therefore we see this being a potential risk of scratching the painted surface if used. We do apologize for the inconvenience, however we cannot stand behind the use of this product for that purpose.
So, essentially, how I (and Rusty) have been using this stuff is correct: Keep it OFF the painted surfaces, keep it to the unfinished brass ONLY. This is the first time I've gotten a solid answer about this stuff, and I did imagine it was NOT good for painted/plated surfaces.
And of course, IF this puts you off using it, that's up to you. I'm certain ALEMBIC doesn't need any finish problems caused by ham-fisted users, nor do they honor any 'self-inflicted' finish problems, and they should not have to fix something that's all my fault. But it is very fast and I'm very careful with it, so do what is best for YOU.
I'm very big on using things that are as inert as possible (I need all the help I can get NOT messing things up), so I can now imagine I'm now looking for a new (harmless) brass polish !
BTW, for the life of me, I can NOT find ANY lemon oil that's petroleum free, even at Whole Foods or Trader Joe's (yes, we have tree-hugging grocery stores in Nashville now !). Anybody tip me off to where I can find any?
J o e y