Michael wrote:
Does anyone know how to remove Crayola Invisible Marker from ivory
piano keys? Warm soapy water didn't work.
Thanks

Usually to remove a discoloration or stain, you use a solvent close in
chemical composition to the staining agent.

In this case, crayons are made of wax, so I'd try something in the mineral
spirits, Kerosene, etc., line rather than alcohols, bleaches, turpentine,
and solvents based on other chemicals.

And unless the piano is more than about fifty years old, the keys aren't
ivory.