Regardless of whether you clean or replace the strings on your player
piano, it is a long and dirty job requiring specialist tools.  Once
you have removed the stack, the piano action and keys, it's time to tip
your player piano on its back using a 'bench truck'; this is for easy
access (and life) to the strings.

So, okay, you have decided to just clean the strings, therefore
requiring the following tools: a face mask is vital -- I had said that
it was a 'dirty job', so preventing the clouds of rust and other crud
from the cleaning process to enter your lungs is vital; and a few pairs
of latex gloves protecting your hands from dirt and cuts.

Then you need a "carborundum rubber" from your piano [tool] suppliers;
it is rather like an old ink rubber but much larger.  You draw the
rubber up and down the full length of the string (watch your fingers on
the protruding bridge pins), dragging off rust and years of crud,
leaving a clean and very bright new-like steel string.  Use a chip of
wood to sit between the bass strings, so as to access the overstrung
steels.

I didn't say that it was easy! The flat of the rubber can be used to
clean the bridge pins, making no difference to the tone whatsoever, but
only for "if a job is worth doing it is..." -- you know how it goes!

Now you have the tubby bass strings to clean; that is even harder!
You need wire wool (and not too heavy a grade as you don't want to
scratch the strings) and a pair of thicker protective gloves.  Getting
the wire into the skin is easy, painful and difficult to remove.  Now
firstly draw a scrunched up piece of wire wool, again up and down the
length of the string and then laterally between the windings, removing
discolouration and crud.  (I like that American term.)

Time for vacuuming the sound-board and inner case.  If there are any
cracks in the sound-board you'd best deal with them, and from the rear
of the piano.  If replacing the strings and tuning pins, then from the
front.  However, that is all a different subject.  This outlined
cleaning process cannot account for the underside of the string; clean
only the top and string sides if that isn't hard enough.

Many years ago I used to use this process for rejuvenating the overall
sound, and to some good and to a point, lasting effect.  Fully
restringing, is however the best way forward, giving the opportunity
to clean and repair the sound-board.  The tone after about six months,
makes the job really worth while.  And only a few days more work.  This
I have done a couple of hundred times as nowadays I don't bother with
just cleaning the strings.

John Oakes