Yellow Keys? Methods for Whitening Ivory vs. Plastic Keys

You have cleaned your keys. You have disinfected them. But they are still yellow.

This is the most frustrating part of owning an older piano. You scrub and scrub, but that dingy cream color won’t budge.

That is because it is not dirt. It is a chemical change.

Before you start experimenting with bleach (don’t!) or sanding (please don’t!), you need to understand what is happening. Here is the truth about whitening your keys safely.

The “Patina” Perspective

First, a reality check. If you have genuine ivory keys, they are supposed to be yellow.

Ivory is a naturalNaturalA symbol used to cancel a previous accidental (sharp or flat), restoring a note to its original pitch.The Savvy Take: Think of the Natural sign as the “Reset Button.” It clears the cache for that measure. Remember, the bar line automatically acts as a natural sign for accidentals from the previous measure, but composers often add “courtesy naturals” just to be safe. Thank them for it.View in glossary → organic material. Just like old paper or wood, it develops a “patina” over time. In the piano world, a slight creamy yellow tint is not considered damage. It is considered character.

However, if your keys are stained dark brown or look uneven, you can try these methods to brighten them.

Scenario 1: Whitening Real Ivory

Ivory reacts to light. In fact, keeping your keys covered in the dark is often what causes them to yellow in the first place.

The Safe Methods

1. Indirect Sunlight: The easiest whitener is UV light. Leave your fallboard (key cover) open during the day. Indirect sunlight can naturally bleach existing discoloration over time.
2. The White Eraser: For surface yellowing caused by grime, a simple white vinyl eraser can gently abrade away the buildup safely.
3. 0000 Steel Wool: Some technicians use ultra-fine #0000 steel wool to polish ivory. This must be done with extreme gentleness to avoid scratching the surface.

The “Old School” Kitchen Trick (Use Caution)

You might hear rumors about using Plain Yogurt or Mayonnaise on ivory. Believe it or not, this is based on fact. The mild lactic acid in yogurt can gently clean and whiten the surface.

• The Method: Apply a thin layer of plain yogurt. Let it sit briefly. Wipe it off immediately and dry thoroughly.
• The Warning: This is risky. If moisture seeps between the keys, it will loosen the glue. Plus, putting food on your piano is generally a bad idea. We recommend sticking to sunlight first.

Scenario 2: Whitening Plastic & Acrylic

Plastic is different. While sunlight whiten ivory, sunlight actually ruins plastic. UV exposure degrades plastic and causes it to yellow further.

The Safe Methods

1. Plastic Polish: A dedicated plastic polish (like Novus 2 or automotive plastic polish) can physically buff off the thin oxidized layer of the keytop.
2. Cory Key-Brite: While primarily a cleaner, this product is safe for all plastics and helps brighten the appearance by removing dulling oils.

The “Retrobrite” Warning (High Risk)

You may have seen YouTubers using “Retrobrite” (high-strength Hydrogen Peroxide cream + UV light) to restore old game consoles or sneakers. Can you use it on piano keys? Technically, yes, but we rarely recommend it for DIYers.

• The Risk: High-concentration peroxide can make plastic brittle or cause “crazing” (cracking).
• The Hassle: You usually need to remove the keys from the piano to do this safely. Soaking keys while they are still on the piano can cause the wood to swell and warp.

Scenario 3: The “Ivoritis” Problem (Yamaha)

If you own an older Yamaha from the 80s or 90s, you might see a strange greenish-yellow discoloration. Technicians call this “Ivoritis”. This is not a stain. It is a chemical breakdown inside the “Ivorite” material itself.

• The Bad News: No amount of scrubbing or bleaching will fix it.
• The Solution: The only fix is usually professional keytop replacement.

What NOT To Do (The Danger Zone)

Regardless of what material you have, avoid these common mistakes.

• No Bleach: Chlorine bleach ruins ivory (making it chalky) and destroys the molecular bonds of plastic.
• No Sanding (Unless you are a Pro): Sanding can restore whiteness, but if you do not have professional equipment, you will end up with uneven, dip-filled keys that feel terrible to play.

The Savvy Verdict

If your keys are clean but slightly yellow, our advice is to leave them alone.

The risk of destroying the textureTextureThe general pattern of sound created by the arrangement of the musical elements (melody, harmony, rhythm). Examples include Monophonic, Homophonic, and Polyphonic.The Savvy Take: Pianists control the entire texture. You are the conductor, the choir, and the orchestra. Always ask: “Is my texture too thick?” If the chords are muddying the melody, thin out the voicing.View in glossary → of your keys is not worth the cosmetic upgrade. Embrace the history of your instrument. If you absolutely cannot stand the color, hire a technician to replace the keytops entirely.