string cleaning

[John M. Formsma]

Thanks to all who responded about the "string cleaning" question.  There
were a number of good suggestions.

One of the reasons that I asked about string cleaning was the possibility
that it might cause a very slight difference in the upper partials of the
unisons.  I am somewhat thinking out loud, but is it possible that rust on
various places on a string might cause that one string to be a little
"heavier" than the others, thereby not allowing some of the upper partials
to line up properly together?  I have noticed that in certain pianos, some
of the unisons have a very slow waaaaah sound.  It is not really a beat, but
just some noise that I could not tune out.  To describe it, it was as if the
first several lower partials were in tune, but there was some additional
noise that I could not identify.  Now, it might be that my tuning skills are
not where they should be, but I was wondering if some of that might be
caused by rust or other junk on the string.  Could that affect the partials
in this way?  When this has been the case, I have noticed some rust on the
strings.  The rust was in spots rather than over all the string.

If this "noise" is not due to something on the string, to what can it be
attributed?

Wondering...

John Formsma