[CAUT] brightening a Yamaha

[Richard Brekne]

Try polishing the hammers with 3M microfiber paper... 30u grit is 
nice... followed by a nice couple seconds of ironing with your electric 
hammer iron. Make sure you have good contact with all three strings 
afterwards... and regulate letoff to 1.5 mm in the area in question.

If that doesnt do it for him... then I'm afraid you're stuck either 
going for harder inside felt or using some juice.

Cheers
RicB