The piano is unique among musical instruments because it also serves as fine furniture for the home. In fact, the term "piano finish" has traditionally been used to describe the highest standards in wood finishing. Properly maintaining that fine finish will enhance your home's decor and preserve the value of your piano.
Basic finish care
Modern Pianos are finished with a variety of materials, from traditional lacquer to modern polyurethanes and polyester resins. Whatever the material, a piano finish is designed to protect the wood from dirt and liquid spills, reduce the damaging effects of humidity changes, and -- in the case of clear finishes -- enhance the beauty of the wood.
Modern finishes are designed to do their job without the additional aid of polishes or waxes. In most cases, a piano finish is best maintained by simply keeping it clean and avoiding exposure to direct sunlight, extremes of temperature and humidity, and abrasion.
1. Avoiding finish damage.
Your piano's cabinet, like all woodwork, is subject to expansion and contraction with humidity changes. Excessive wood movement can eventually cause the finish to develop tiny cracks and even separate from the wood. Moderating the temperature and humidity swings around the piano will help to preserve its finish as well as its overall structure and tuning stability.
Locate the piano in a room with a fairly even temperature, away from drafts, dampness, and heat sources. ALWAYS AVOID DIRECT SUNLIGHT -- it will age the finish prematurely and cause color fading.
To prevent scratches, never set objects on your piano without a soft cloth or felt pad. Never place plants or drinks on a piano, because spillage and condensation can cause major damage.
2. Dusting your piano
Dust is very abrasive, and can scratch the finish if wiped off with a dry cloth. To avoid scratching, dust the piano lightly with a feather duster. Alternatively, wipe lightly with a soft damp cloth to pick up the dust, followed immediately with a dry cloth. The cloths should be soft cotton such as flannel, because coarse or synthetic fabrics can scratch some finishes. Wring out the damp cloth thoroughly so it leaves no visible moisture on the surface.
To avoid creating swirl marks, always wipe with long straight strokes rather than circular motions. Wipe with the grain for natural wood finishes, or in the direction of the existing sheen pattern for solid-color satin finishes.
Because some exposed parts inside your piano are fragile, it's best to let your technician clean these areas.
3. Cleaning the finish.
To remove smudges and fingerprints, first dust using the damp/dry cloths as above. If heavier cleaning is necessary, dampen your cloth with a small amount of mild soap solution. A common product is Murphy's Oil Soap, available at most grocery and hardware stores.
4. To polish or not?
Before using polish on your piano, be sure it is actually necessary and beneficial. In general, most manufacturers recommend against using polishes because of the potential for damage to the finish and contamination of other parts of the instrument.
Common household products such as "lemon oil" or inexpensive "furniture polish" should be avoided. Despite the labels' claims that they "protect" the finish or "feed" the wood, they offer no protection from scratching and can actually soften the finish if over-used. Worse, they often contain silicones and oils that contaminate the wood, complicating future refinishing or repairs. Silicone is especially dangerous because of its tendency to spread within the piano, sometimes causing extensive internal damage. Avoid aerosol products altogether since the over-spray can contaminate piano strings, tuning pins and action parts.
An appropriate polish can help to restore luster to a dulled finish or reduce the tendency of some finishes to show fingerprints. However, it should be applied sparingly and infrequently, and all excess should be wiped clean with a soft dry cloth so no visible film remains. To prevent scratching, always dust before polishing. Specific recommendations follow.
5. Removing a heavy polish build-up.
If your piano's finish appears gummy, oily, or streaked, it may be contaminated with too much or the wrong type of polish. Adding more polish will not correct this problem. Instead the finish should be thoroughly cleaned, then evaluated for any further treatment.
To remove accumulations of old polish, use a cloth dampened with a mild soap as in item 3 above. Wring the cloth thoroughly to minimize wetting of the finish, and dry the surface immediately. Test a small area first to make sure the washing does not cause white marks or softening of an older finish.
If stronger cleaning is necessary, look for a product called "wood cleaner and wax remover" at hardware or wood workers supply stores, or ask your technician for a suggestion.
Once the original finish is clean, you can either leave it as is or enhance the gloss and clarity with an appropriate polish according to the finish type listed below.
Care of specific finish types
The two most common piano finishes are lacquer and polyester. Either material may come in clear, black, white, or other colors. Check your piano's owner information booklet to determine the type and recommended care of your piano's finish, or ask your technician or dealer for help if you're not sure.
Most, but not all, American-made pianos have lacquer finishes. They may be satin (dull sheen), semi-gloss, or high gloss.
Cleaning -- For general dusting and cleaning of lacquer finishes, see items 2 and 3 preceding. Be especially careful to avoid scratching high gloss finishes by using only very soft, clean cloths and wiping with light pressure. For satin finishes, always rub in line with the existing sheen.
Polishing -- Satin finishes are intended to be dull and will normally have a poor appearance if a gloss-producing polish is applied. If desired, a polish may be applied to gloss or semigloss finishes. Two common products are Guardsman Furniture Polish and OZ Cream Polish. Your technician may carry these or other products especially recommended for piano care. Note the precautions under item 4 regarding selecting and applying polishes.
When cleaning or polishing a lacquer finish, avoid hard pressure on sharp corners and edges since the finish can easily wear through to bare wood.
Most Asian and European pianos have polyester finishes in satin or high-gloss (called high polish). This material is harder and more scratch-resistant than lacquer, and best maintained by simple dusting and cleaning.
Cleaning -- Use the same procedure as for lacquer.
Polishing -- Satin polyester looks best when simply kept clean. Avoid gloss-producing polishes, which leave satin finishes looking shiny but scratched. High-polish polyester finishes need only be kept clean to maintain their gloss. However, high-wear areas such as the music desk may eventually develop a hazy appearance caused by many fine scratches. These areas can be buffed back to a high gloss using a product designed to remove tiny scratches from fiberglass boats or plastic windows in convertible cars. Two such products are Meguiar's Mirror Glaze #17 Plastic Cleaner, and Meguiar's s Mirror Glaze #9 Swirl Remover--available from marine supply, auto-parts, or automotive paint supply stores. Your technician may carry special products for this purpose, or can recommend a local source.
Dents. scratches, and chips sometimes occur, spoiling the appearance of an otherwise perfect finish. Such damage can usually be corrected by a specialist in "finish touch-up". Your piano technician may perform this service, or can offer a referral.
Cleaning Your Keys
Piano keys eventually become soiled with accumulated oil and dirt from fingers. To clean your white keys, use a soft cloth dampened with water and a small amount of mild soap. Avoid solvents. Make sure the cloth is thoroughly wrung out, and wipe the keys back-to-front rather than side-to-side, so excess moisture and dirt will not seep down the sides of the keys. Clean only a few keys at a time drying immediately with a clean cloth.
Ivory keys are porous, and excessive moisture can penetrate and loosen their glue joints. Also, a dirty or brightly colored cleaning cloth can transfer stains into the ivory.
Clean sharps in the same manner, but use a separate cloth for painted wooden sharps to avoid black stains on the white keys.
Finish Care Steps
Locate your piano to avoid direct sunlight as well as excessive temperature and humidity changes.
To avoid scratching, always remove dust first with a damp cloth or feather duster before wiping with a dry cloth.
Never place drinks, plants, etc. on the finish.
Avoid placing vinyl or rubber in contact with the piano.
Make sure that piano lamps, etc. have a felt-padded base.
Avoid touching piano strings with fingers or damp cloths.
Delicate parts inside your piano should be cleaned only by your technician.
Use polish sparingly, if at all.
Avoid aerosol products.
Read labels carefully, and avoid any product containing silicone.
Before playing, always wash your hands to prevent staining the sides and tops of the keys.
Piano Technicians Guild Technical Bulletin #5