How to carefully clean ivory, ebony, and plastic piano keys.
In older pianos, the white keys are made of ivory, the black keys of ebony. In newer pianos, all the keys will probably be made of plastic.
Cleaning ivory piano keys
You need to be careful when cleaning ivory piano keys. Ivory is delicate. Many liquids can harm it, not only harsh chemicals but even plain water. Excessive moisture can cause the keys to warp or can loosen the glue that holds them in place. Some experts say that it’s best to clean ivory keys without using any liquids at all, while others do recommend using moistened cloths.
Dry cleaning ivory piano keys
Ivory absorbs oil from fingers, and it stains easily. For the best results, wear white cotton gloves while cleaning the piano.
For routine cleaning, you should dust the keys using a soft paintbrush or duster.
If the keys are stained, you can clean them gently with a white vinyl eraser or with a product called Groomstik, which is available at museum supply houses.
If the keys are yellowed, you may be able to whiten them by rubbing with very fine (0000) steel wool, although this might change the way the keys feel when the piano is played.
One note of caution — if you have an antique piano, yellowed key may be considered desirable because they show the piano’s age, and if you get rid of the yellowing, you might actually lessen the piano’s value.
Using moistened cloths to clean ivory keys
The most cautious experts recommend using only the dry cleaning methods described above, and then calling in a professional if those methods aren’t sufficient — especially if you have a valuable antique piano. Many others, though, do recommend using damp cloths moistened with one of the following: water alone, or water with a small amount of mild soap, or rubbing alcohol, or a commercial product made specifically for cleaning piano keys (available from your piano dealer or tuner). NEVER use chemicals or solvents.
Whichever cleaning agent you use, you should start with a clean, white cloth. Dirt and brightly colored cloths can stain ivory keys. Use very little liquid, just enough to barely moisten the cloth, and wring the cloth out thoroughly before you start to use it. Clean the keys from back to front, rather than from side to side, so that moisture and dirt won’t seep into the spaces between the keys. Clean each key individually, and wipe it dry immediately with a clean soft dry cloth.
Cleaning ebony keys
Clean the ebony keys the same way you clean the ivory keys, but use a separate cloth. If used on ivory keys, a cloth that has been used to clean ebony keys may leave a dark stain.
Cleaning plastic (acrylic) piano keys
Plastic keys are not as delicate as ivory keys, and can be safely cleaned using a cloth dampened with water and mild soap. Wipe dry with a clean cloth. Don’t let the keys get too wet, and don’t let the water run into the spaces between the keys.
Note: If your piano has ivory keys, leaving the cover open will help keep the keys white because sunlight bleaches ivory, but if your piano has plastic keys, it’s the opposite — keeping the cover closed will help keep the keys white because sunlight yellows plastic.