Indeed, I’m a big fan of aluminum grills for bathrooms and such. These speakers have magnetic grills and the specs don’t mention the material but I’m guessing it’s ferrous so rust could be an issue. My plan was to clear coat them with Plastikote after painting. I have a steel grilled speaker in my en-suite that I did this to and it’s been fine for years.

[Link: plastikote.ca]

Thanks for your reply.