One of my clients owns several Piano stores in our area and I have learned how to clean pianos really well and easily. Thought maybe some people out there would be interested in my methods.
First I use a Bona Dusting pad for ease of use, softness and how fast it will dust a large grand piano. When the piano is fully open 
there are parts of the lid I cannot reach. With the Bona wand and pad this is not a problem. When using this pad no other product is needed to dust as this pad really grabs the dust well.
Next is removal of finger prints. I use Murphy’s Oil Soap, mixed and placed into a spray bottle. Soft microfiber cloths are folded in half and I spray them just enough to dampen but not very wet. Wipe fingerprints off with damp cloth and dry with a microfiber cloth. Done. Yes, it is that easy.
Never ever use furniture polish of any kind on any kind of piano. For whatever reason, it has been found that over time they actually ruin the finish on pianos.
Cleaning inside a grand or an upright piano. 
Dust is an enemy to sound and to electronics. Using a vacuum with soft bristle tools, gently go over strings with this tool as well as any flat areas. In grands one has to get underneath the strings and this tool will do so easily. In addition to these my local vacuum store sold me a mini-micro tool kit which attaches to most vacuum hoses. This kit has very small attachments allowing a person to clean in very tight spaces, like on a computer or between piano strings.
Keys. Never clean piano keys with any product that contains ammonia. Murphy’s Oil Soap would be a perfect cleaner for cleaning the keyboard of any acoustic or digital piano. Applied the same way as above by spraying onto a soft cloth and rubbing the keys gently removing oils and dirt. Never spray anything directly onto keys.
Please let me know if I have missed anything but I do not think so. Every week I clean well over a hundred pianos and these are the methods that I figured out over time. I wanted a simple, easy method of cleaning a large grand piano in a timely fashion. These methods work and I use them regularly.
Deb
