well, i just applied a few drops of wd40 with an eyedropper, and it removed 99% of the static noise.
after several minutes, black carbon deposits started to seep out directly behind the knob, which i wiped with a cloth.
it looks like the wd40 flushed it out. The carbon deposits might be the thing that's causing the static.
now, either the wd40 has gathered all of the carbon dust into an oily suspension like motor oil, or it has started to deteriorate the carbon ring inside....... I don't know.
plus, I don't think I've seen anyone say 'oh no! wd40 killed my sub!"
wd40 may not be for most volume pots, but it seems to be safe for the klipsch promedia.