I bought my Yamaha C3 grand piano in 1992 for $10K out the door, and played it on and off for 20 years. I’ve always been happy with it – mostly with the keyboard. It just seems so precise and perfectly made. But the key tops get really dirty and cannot be cleaned by any normal method. Why is that?
When I bought it, the saleslady mentioned the keys are covered with something called Ivorite, which is a proprietary material Yamaha created that is supposed to feel like real ivory, without killing any elephants. They say it is porous enough to absorb sweat and avoid finger slips. So that would account for the dirt. It absorbed sweat and dirt over the years.
There are web pages indicating that Yamaha later determined this was a mistake, and they will actually replace the key tops with a newer Ivorite formulation which does not stain. I really can’t imagine doing this, so I decided I would simply take some fine steel wool to one of the keys and see what happens. Turns out, this worked.
So I removed the entire key action assembly (a couple of large wing-nuts under the keyboard) and brought it to another room where I don’t mind steel-wool residue all over the place. I removed the long strip of wood that holds the keys down and set it aside. That way I can lift the keys up higher than they normally can be lifted.
Then I lifted each key separately and placed a block of wood under it to hold it in place under the pressure required for the steel wool, and rubbed. This took some work, which probably meant I was using the finest steel wool possible which would still work. I was using #00 for this and rubbed until all the stain was gone. Steel wool fragments get all over the place, so I used a compressed air blow gun to clean things up periodically. Probably best to do this outside – you don’t want to get steel fragments in electronics, for example.
When done, I repeated the process (with less work and pressure) using #000 steel wool, as a finishing grind, which was the finest I could get at Home Depot. One final compressed air cleanup and it looks new again.
Then in an attempt to prevent the problem from happening again, I coated each white key with car polish, let it dry, and wiped off the residue. This makes the Ivorite keys a bit slippery, but my hope is that the polish will be removed on the surface, revealing the microscopic grooves in the Ivorite left by the #000 wool, while leaving the keys much less porous than they originally were.
We’ll see what happens over time. Worst case, I guess I can complain to Yamaha.