Symptoms
- Keys look cream, yellow or uneven in color compared with each other
- Darker patches where fingers play most, or stripes along the grain
- Fine lines or small cracks on the key surface
- Keytops that are chipped, lifting at the edges or missing
Likely causes
Ivory kept in the dark
Real ivory yellows when the fallboard stays closed for long periods. Gentle daylight slows and partly reverses the change.
Aging plastic
Older celluloid and acrylic keytops discolor from age, heat, cigarette smoke and kitchen grease, and this does not reverse.
Dirt and skin oils
A film of grime builds up on the playing area, especially in the middle of the keyboard, and looks like yellowing.
Wrong cleaning products
Alcohol, solvents and harsh cleaners can etch plastic and stain or crack ivory.
What you can safely check yourself
- 1Look at the front edge and surface of a white key: ivory usually shows a fine grain and a visible seam between the head and the tail; plastic is uniform with no seam.
- 2Clean with a soft cloth very lightly dampened with water and a drop of mild dish soap, one key at a time, wiping front to back.
- 3Dry each key immediately with a second cloth so no moisture runs down the sides into the key wood.
- 4Use separate cloths for black and white keys so black dye does not transfer.
- 5Leave the fallboard open during the day so ivory gets indirect light, but keep the piano out of direct sun.
What not to do
- Don't use bleach, alcohol, acetone, toothpaste or household sprays on keytops.
- Don't spray anything directly onto the keys; liquid can seep between them into the action.
- Don't put the piano in direct sunlight to whiten keys; it damages the finish and can crack ivory.
- Don't glue loose keytops with superglue; it stains and makes later repair harder.
Quick fixes vs. call a pro
You can usually handle it
- General grime and fingerprints
- Mild, even yellowing of ivory
- Routine cleaning every few weeks
Call a technician
- Chipped, cracked or lifting keytops
- Missing keytops or badly mismatched keys
- Full replacement of a worn plastic keyboard
- Advice on ivory restrictions before selling
What a technician will do
A technician can reglue loose keytops, patch chips, or replace individual or full sets of keytops with modern acrylic or imitation-ivory material. Regluing a few tops takes under an hour; recovering a full keyboard is usually a workshop job taking a few days.
A piano holds about 18–20 tonnes of string tension. If a fix means opening the action, turning tuning pins or working near the strings, leave it to a technician.