Don Barton asks how to get rid of verdigris in a Steinway piano action. 

You might start with an Internet search of what causes verdigris.  It is

a big problem for player technicians as well as Steinway technicians and

has been debated over and over.  



It is a chemical reaction between acid fumes in the  air and brass.  The

center pins in Steinways were apparently poorly plated, allowing the

fumes to pass through the nickel plating, thus creating the verdigris.



Nickel plating is actually porous, and that was one reason chrome plating

became so popular on car bumpers.  Nickel-plated bumpers would rust, since

water could actually pass through, creating rust.



On three of the piano tech forums the technicianss all agree that the only

way to stop verdigris is to replace all the parts with new ones.



Don Teach