keys. if you touch the cloth to white keys it may transfer black color or dust to your white piano keys. carefully and properly wipe black piano keys after white keys.
by using a cotton dry cloth, you need to wipe the keys to clean soap residue, make sure you wipe back to the front so that nothing gets between the piano keys.
you need to do special treatment to remove fingerprints, make a solution with four parts of water and one part of vinegar. take a soft white cloth, dip it into the solution, make sure you wring it out well, so the cloth is only damp not wet. now separately 