In home piano tuning in Billerica, MA. This is a Baldwin vertical piano made in 1994. Piano stays in tune very well. Unfortunately the bass strings sound very dull. They may need to be twisted for one more turn. Didn't try it this time, will talk to the customer to see if she wants to give it a try.
Some hammers are hardened through time. When they strike strings, the sound is very harsh. The needles helped soften the wool on the outside of hammers. The sound is softer after some stabs. Happy with the result.
The yellow colored leather is hardened, making squeaking noise. Ms. Jessica Mass from Interlochen Summer Camp taught me to use ivory soap as lubricant. It worked! The noise disappeared!