Listen...
I've owned several pair of Solos and received one particular pair which were ALL Piano black with scratches everywhere!!
The less than honest AudiogoN'r shipped them in dusty plastic bags which wreaked havoc on the Piano finish.
The finish on the speakers is NOT PAINT, so I would highly advise against using any of the above recommended products.
The tops are actually acrylic (plastic). I used Novus Plastic polish which has a 3 stage product for removing everything from very minor scratches to larger and deeper scratches.
Here's a link to their website http://www.noscratch.com/novus/
I bought mine at Tap Plastics. I think it was about $25 for the whole kit. There's PLENTY in each bottle, so you only need one bottle of each. The #1 spray polish is awesome and the ONLY thing I would recommend using to clean your speakers. If you get a big build-up of dust, I recommend gently wiping them with a brand new damp sponge. It helps lift the dust off of the speakers w/o letting dry particles grind into the finish.
Feel free to contact me privately if you have any questions.
And...NO...I don't work for the company. I'm just a satisfied customer :-)