Basic Piano Care
Keep your piano in tune. It was specifically designed to be tuned to the international pitch standard of A-440 cycles per second (with a few exceptions). Your piano will sound its best and give you the most pleasure when it is tuned regularly and kept in proper playing condition. Keep your piano clean. Keep the keyboard covered when not in use to prevent dust from accumulating (although ivory keys need some exposure to light to prevent yellowing). Clean keys by occasionally wiping them with a damp cloth and drying them immediately. If accumulated debris can't be removed with a damp cloth, try wiping the cloth on a bar of mild soap or moisten with dishwashing detergent before wiping. Do not use chemicals or solvents to clean piano keys. Call a qualified piano technician to remove anything from the keys you can't wipe away.
To maintain the piano's finish, wipe the case with a damp cotton cloth to remove fingerprints, or polish with a reliable emulsion-type, water-based solution following the manufacturer's instructions. It is important that the cloth be moistened, as dust on the piano's surface is a fine abrasive, and using a dry cloth to clean your piano will damage the finish over time. Avoid aerosol spray polishes and products that contain silicone.
The maintenance of the inner working of the piano and regulation should be left to a qualified piano technician. Resist dusting the inside of your piano, never oil the moving parts, or use moth or insect repellents.
Try to maintain a fairly consistent temperature and humidity control in the room where your piano is placed. It's important to keep your piano away from a heating register in winter, an air conditioning vent in the summer, a fireplace, a frequently opened window or outside door, and direct sunlight.
Play your piano regularly. You'll get the most enjoyment from it and also reach your potential much faster. A disadvantage to idle pianos, assuming they also suffer a service lapse, is that a detrimental condition or environment can be more difficult to identify, and an escalating problem can result in damage that might not have occurred with regular service. Tuning a piano after years of not having been tuned often requires a pitch raise. As a piano ages, it may begin to develop more major problems which your technician can help you assess. You may look into rebuilding or reconditioning the piano.
Keep all drinks and standing liquid containers, including potted plants off the piano. Should spilled water reach the action, notify your piano technician immediately. In many case, once liquids are spilled, the damage is irreversible without very expensive repairs, which is why prevention is the safest rule to follow.