Piano keys- I have real, antique ivory keys. How can I make them whiter & keep them white?

Question

I've heard a lot of contradictions to this. I know that light will cause newer piano keys to yellow, since they are plastic. However, what about real, ivory keys? I have an antique upright grand built in 1904. I read on a couple sites created by piano tuners that light is actually GOOD for them & to make them white again, expose them to light by keeping the key lid up. HOWEVER... my tuner says the opposite, that light will only make them more yellow & I should try & keep my lid closed whenever I'm not using it.

So which is it?

Any suggestions, too?

Also, if you have an antique piano, I'd love to hear from you, too. Tell me about it. I just love them :)

Answer 1

Create a very mild solution of water and dilute detergent such as Orvus brand.
Using the solution, very slightly dampen a cotton swab, a cotton ball, or a fresh cotton rag, and gently wipe the ivory surface. Dry immediately—if necessary—as any excess moisture left on the surface can cause the ivory to split.
Very slightly dampen cotton with water and wipe off any detergent residue. Again, dry immediately.
Do not soak the ivory. Also do not use ethanol (or any type of spirits), which is sometimes recommended in some older restoration guides. Also do not use vinegar or lemon juice—both are very acidic.
Direct quote from a professional museum objects conservator: "I would stick with the dilute detergent cleaning and avoid things like toothpaste. The abrasives are a problem, as well as the other components in pastes that might be difficult to get out that will harden and become unsightly."

Ivory, by nature, will darken in the dark and lighten in the light. If you wish to safely brighten ivory, simply expose it to normal light levels. (Avoid dramatic temperature changes such as that which may occur with prolonged exposure to direct sunlight.)
There is a dangerous "brightening" formula circulating containing Drano (based on sodium hydroxide) and high-concentration hydrogen peroxide combined with exposure of the ivory to a UV light source. This formula has a very high pH (well above 10) and will break down the ossein in the ivory. While there may not be any immediate visual symptoms of damage, the resulting long term effects will be brittleness and cracking. As such, this harsh formula is not recommended.

Answer 2

Ok this might sound odd but I collect vintage toys and have actually used whitening toothpaste to clean them and have had good results

Answer 3

A tooth paste ("with a whitner") and a tooth brush.