I had bought a backup mixer to use for dirt cheap and decided to clean it all up, inside and out. 1 out of the 5 sliders has a dust protector to keep dust from getting into the fader, all the other faders without the protector were loaded with dust. Where can i find these fader dust protectors (or however they're called). The faders are Noble's, measuring 3.5" long, .5" wide. Are there other alternatives to use? Thanks!