I have researched this question with no results. All I find are tutorials on cleaning pianos, but nothing about the effect dirt and dust have on a piano.

I have a Symphonic baby grand piano made in 1912, and the insides look a little dirty. Could dust or dirt affect the sound of the piano, or even the action of the keys? I notice the bass keys are much harder to press than the treble keys (I know this is normal for grands, but the difference on this piano seems abnormal), and I'm not sure if dirt can cause that. Could it also affect the dampers, making them take longer to mute the strings?

Basically, what effect does dirt and dust on the insides have on the piano sound, action, and functionality, if any at all? Any answers to this question are greatly appreciated!

  • If it has been out of use for quite a while then it probably needs tuning. The tuner could probably assess its condition better than we can.
    – badjohn
    Dec 30, 2020 at 10:32

2 Answers 2


It's going to affect just about everything. But to what extent, is another question. String windings that are full of dirt and dust will not sound as bright as clean ones. Rusty single strand strings (the higher part) won't vibrate as well as un-rusty ones.

The felt on hammers will be affected by ingrained dirt. The moving parts (hundreds of them) won't respond and recover as efficiently as they would when clean. Flexible parts will be stiffer when dirt is covering them.

After more than 100 years of dirt accumulation, just about anything would need a good clean, wouldn't it?

  • The guy who had the piano before me had it for I think 10 years. He had all the keys, hammer and damper felts replaced. The strings don't look like they're in bad situation. The only thing is the inside is dirty, and the action is really heavy at the bass. It's not unbearable, but a little abnormal. Maybe that's how the piano was built? I'm not sure. All I know is it's dirty inside, and I wasn't sure if that would wreck the sound or explain the tough action. Apr 4, 2020 at 7:37
  • What make is it? If it's a Yamaha I'm not surprised by the hard action, and others seem to be similar. If it's general dirt, then a vacuum will clear that. A good piano tuner will provide guidance, so it shouldn't be too long till that opportunity comes along, should it?
    – Tim
    Apr 4, 2020 at 7:46
  • Mine is by Symphonic. I haven't heard of them before, only this piano. Apr 4, 2020 at 16:57
  • No, nor me.....
    – Tim
    Apr 4, 2020 at 17:23

Not much, unless it's so extreme that it's actually impeding mechanical action. I certainly don't think you can blame dirt for a heavy bass-end action. Perhaps for ONE sticking note.

  • Part of me thought that, but I wasn't entirely sure. Thank you! Apr 3, 2020 at 23:36

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