This very pretty Young Chang grand piano was coated with a fine layer of soot from a kitchen fire. The repair was to remove all the strings, clean the piano thoroughly and install new strings.
When a piano is exposed to soot, the bass strings collect soot into the copper windings. This cannot be cleaned. The result is a very tubby sound and complete loss of tone. The treble strings will have a loss of tonality as well as the soot acts as a corrosive to the steel. New strings - new sound.
The piano is then "bagged" and the use of an ionizer for a few hours removes the smoke smell from the piano.
This piano was then power-buffed and polished.