For years I have cleaned piano gloss speakers using the following method with perfect results:
1) Lightly dust the speakers with a Swiffer Duster. This will remove the loose dust particles without abrading the surface.2) Lightly mist the speaker with any high-quality auto detail spray. I had good luck with Mothers.3) Spray the Mother detail spray onto your NEW microfiber cloth, folded into quarters. Gently wipe the finish until you see the detail spray start to disappear. Flip over the cloth for a final buff and you're all set.4) As long as the speakers are not touched, usually you can get excellent results from just going back to Step 1, above, and not having to use the detail spray steps.
To fix existing surface scratches on used speakers I purchased, I have used Turtle Wax Jet Black Car Polish and plenty of elbow grease with good results.
1) Lightly dust the speakers with a Swiffer Duster. This will remove the loose dust particles without abrading the surface.2) Lightly mist the speaker with any high-quality auto detail spray. I had good luck with Mothers.3) Spray the Mother detail spray onto your NEW microfiber cloth, folded into quarters. Gently wipe the finish until you see the detail spray start to disappear. Flip over the cloth for a final buff and you're all set.4) As long as the speakers are not touched, usually you can get excellent results from just going back to Step 1, above, and not having to use the detail spray steps.
To fix existing surface scratches on used speakers I purchased, I have used Turtle Wax Jet Black Car Polish and plenty of elbow grease with good results.