Finish stains

[Clyde Hollinger]

Friends:

A church I serve has a 4-year-old Yamaha P22 studio piano with a medium
oak finish.  The fallboard is kept closed whenever the piano is not in
use.  At the points where the fallboard contacts the little rubber
buttons on the top edge of the keyslip, dark stains which are
considerably larger than the buttons have developed on the fallboard. 
It's as if the stain has leached out of the rubber buttons into the
finish or the wood and is pretty ugly when the fallboard is open.

Has anyone else seen this?  Are the stains easily removed in any way
without a refinish job?  Thanks for any help.

Clyde Hollinger, RPT
Lititz, PA