Buffing with toothpaste and cleaning with milk helps remove yellow staining from ivory keys in many cases. An ivory scraper is necessary to remove particularly difficult stains. Exposing the keys to direct sunlight can prevent them from yellowing in the future. Plastic keys, however, should not be exposed to sunlight, as this can cause them to become discolored. To determine if your piano is made of pure ivory keys, look at the keys closely. You should see a fine, straight split in the keys. This indicates that the keys were bonded together using only ivory pieces. Keys made of other materials do not have this separation.
- Buff the keys
Use a mild, white toothpaste to gently buff the ivory piano keys. Wipe the toothpaste off the keys with a cloth that has been dampened in milk, and then dry the keys immediately.
- Clean the keys with milk
If the piano keys are made of pure ivory, clean the keys with pure milk. Don't use an abrasive cleaner such as lemon juice. This wears the ivory keys down over time.
- Use an ivory scraper
If the stains are difficult to remove, an ivory scraper can do the job. Consult a professional before use to ensure you are using the scraper correctly. If you do not use the tool the right way, the keys may have to be removed and cleaned by a licensed technician.