Soundboard restoration

[waco@ari.net]

I'm currently working on the soundboard of a 1904 Steinway "O".  During its life
lots of cleaning was done with inappropriate methods, and the sound board has
numerous blemishes perpendicular to the grain of the wood where it was dented
and scratched.  Other that sanding down through the blemish is there any method
that will remove them?  Bleach?  Stain?  Steam?

Any hints on this would be appreciated.

Frank Weston