That second hand piano that you have recently
purchased contains a lot more than the hammers, strings, and other
pieces of wood and metal. The keys rest in what amounts to a
storage space. This storage space has probably been unseen for
anywhere from 50 to a hundred years. The question is, what lies
hidden in this storage space. This isn't urban myth, nor is it
anecdotal observation. The dirt and debris that settles in a piano
over a space of a hundred years is to be seen to be believed. If
you do shop for a piano from a dealer, ask that he remove the keys
for you to have a look underneath. Look at the interior underneath
the keys. Minimally, this should be clean, free of rubbish.
Maximally, the interior felts, paper washers, and everything else
that contributes to smooth operation of the key should be in good
condition.
like our computer keyboard ah??
can open one??
never strike my mind about this... 
