Best practices for speaker cabinet care

The only type of wood finishes that need any "conditioners" are wax or oil finishes. Anything other type of finish, the wood is completely sealed and anything applied to the finish just sits on it never penetrating the finish. If the veneer finish gets a film on it from cooking, smoke, or other air pollutants, a furniture cleaning solution is what you need, not a wax. For painted finishes, something like Meguiar's Instant Detailer works well to clean and shine without leaving a film buildup. Just make sure there's no dust on it to cause micro scratches before using. 

• @zlone, I've had a pair of black piano lacquer Tidal Piano speakers for more than ten years. When they need more than dusting I dust them first with a new Swifter duster and then use a newly laundered micro-fiber cloth and Mequiar's Instant Detailer. Black lacquer shows every little thing you don't get off and it sometimes takes repeated applications and buffing to get it like a black mirror. Works great on my REL black subs too. FWIW, Steinway pianos says plain water on a micro-fiber cloth works fine for most cleanings of their finish.

@zlone,

No, the Meguiar's Instant Detailer will definitely not remove scratches as it's just a clear liquid with no abrasives. I've never had occasion to try and remove scratches from my speakers. I'd imagine one would have to be skilled in using polishing compounds and a buffer to do that.