Steinway mystery knuckle felt

[Tom Driscoll]

Subject: Steinway mystery knuckle felt

Hello list.

Does anyone have an idea about what is the purpose of that small piece 
of felt carefully glued next to the knuckles in this Steinway A 1881 
action ?  Picture attached.

Regards

Stéphane Collin
	
Verdigris Sponge? <G> 
	Tom Driscoll