I've been reading the thread about piano bass strings and have
one caution: rejuvenating the wound strings may reveal inharmonic
partials (overtones) that were previously lost in the dull, tubby
sound.  Or maybe the "treatment" puts kinks or loose spots in the
windings that cause these out-of-order overtones.

Years ago I worked over the bass strings of my Weber Duo-Art grand,
both running the knot along each string and winding about two or three
twists in the string when putting it back on its hitch pin.  I think
I first tried just the twist, got some result, but wanted to go the
whole route and work the dirt out of the windings.

This brightened up the strings all right, but one or two now have
a sour overtone -- actually a 5th harmonic that isn't quite right and
has a bit of vibrato to it.

Just a warning to maybe let sleeping dogs lie, if that bass isn't too
awfully dull.  Of course if you're prepared to replace the strings,
you have nothing to lose.

Mike Knudsen