How To Clean Piano Black Speaker Finish?

+1 Millercarbon.  Griots speed shine is awesome stuff!  I use that on my car, after 3 days of wet sanding, buffing, and waxing of course ;) Primo stuff.

But yeah, treat it like a cars finish.  Pretty much exactly as Millercarbon describes.  Once you have the finish dialed in Speed Shine is all you need.  I would recommend spraying it on your microfiber towel, not directly on the speakers as to not get overspray on the drivers.  I’ll only use damp microfibers on the fronts next to the drivers.  I’ll also use a soft paintbrush to dust the my mid bass drivers (particularly on the surrounds).

I sprayed mine with furniture Pledge and fingerprints show much less.  I suspect anything containing light wax can do the same.

Millercarbo I will certainly not let you near any of my Porsches. Stereo 5 you are going a fabulous job if you have not got swirl marks so far.
Instead of using water you could use an instant detailer like Meguires 34
which has a little wax in it and will remove finger prints. If you polish the surface do not wipe in straight lines! Polish in brisk circles never staying in any one place. Here is the reason. If you wipe in straight lines the swirl marks you generate will all be visible from one angle and from that angle the finish will look like absolute crap with hundreds of straight line marks. If you wipe briskly in circles constantly moving, the marks you create depending on the light will only have very short segments visible at any one angle in a very random pattern which is not near as noticeable as all the marks going one way. If you do develop swirl marks Menzerna 3800
will take them out safely with a clean microfiber cloth and polish the surface at the same time. Autogeeks carries Menzerna which is the German version of Meguires. The difference between a scratch and a swirl mark is the swirl mark you can not feel but the scratch will catch the edge of your finger nail. If you were to get a scratch, leave it alone. The paint on this stuff is very thin and it would be easy to rub right through it then you have a real mess. It would have to be filled first then flatten out which is a whole other process
Millercarbon, Paint cleaning clay is only for use on the most contaminated surfaces before rubbing the car out. I never use it on my cars because they never get that contaminated because nothing ever sticks to them 
(CQ UK 3.0) Clay is a swirl mark generator. Mequires #4 will take the paint right off his speaker. He would use Meguire's 205 (they changed their numbering system just to confuse everyone.)

mijostyn, in another train wreck of a post:

Millercarbo I will certainly not let you near any of my Porsches.

This is for everyone else since mijostyn as he is about to discover has crashed and burned and lies smoldering. I have the first place concours trophy from Whistler Weekend, a multi-region Porsche Club of America event where 120+ Porsches compete, to serve as my bona-fides. 

Concours as mijostyn is only now learning is a competition where cars are judged on perfection, particularly as regards paint and finish. In plain English its a car show, albeit one judged to incredibly high standards. I never in my life saw a car at a car show come anywhere near even the average car at a PCA multi-region concours.

No worries mijostyn, I wouldn't come within a mile of your Porsche. Even if you had one.

I've always had great results by first removing the dust with a Swiffer Duster, then using a microfiber cloth and Mothers quick detail spray. I would spray a little on the speaker, then some on the cloth. Then, gently wipe the speaker to remove any finger prints, turning the cloth over to the dry side for a final buff. I have yet to have any issues using this method on any of my speakers or subs.