Alcohols and paint thinners
Virtually all the major piano manufacturers offer cleaning and care instructions on their web sites. Even some disinfectants like Purell and Lysol are mostly alcohol or phenols and should be used well away from the piano. Solvents like alcohols and paint thinners can damage the finish and the key covers. Bleach of any variety can damage the piano for sale finish and the wood parts of the piano. You should keep all strong chemicals and cleaners away from your piano. If the water is small in amount and not readily accessible, usually the best thing to do is to simply let it evaporate, rather than risk mechanical damage to the piano.
