Top: before and after hammer reshaping. This can’t make the hammers new again, but can restore some of the tone, even out the sound, and improve sustain. In this case, it was a helpful measure on an old piano where replacing hammers wasn’t currently in the budget. In a perfect world, this should be done every few years on all hammers, especially on high quality or heavily used instruments.
Bottom: new hammers on a 100-year-old upright. This is the ideal solution for this age instrument, where the original hammers really have nothing left to give.
Many people do not realize that hammer quality and maintenance are some of the biggest factors in the tone quality of a piano! They are worth everything you put into them.