Heavy hammers

[Ted Simmons]

A piano teacher bought a used Yamaha G3 which had a nice touch before the
rebuilder installed new hammers.  Now the touchweight is 65 grams and she
and her students are complaining about the heavy touch.   I had a set of
used Yamaha C3 hammers in my shop and substituted a couple of those hammers
for the heavy ones and the touchweight dropped to 53 grams.

What is the most expeditious way to remove some of the weight from the
hammers?  I don't like the idea of using a sandpaper paddle to take that
much weight off; too labor intensive and with today's modern tools there
must be an easier way.  How would the list members handle this?

Ted Simmons
Merritt Island, FL