[scooby214]

Ive always had good luck using WD-40 in vintage vol & tone controls that are repairable without having to take them apart for closer inspection. Deoxit works great on bandswitch connections etc. For hairline crack repairs of the orig carbon-trace & control taps repairs, you can also try using automotive rear-window defroster repair paint avail from auto-supply stores. In some cases,the defroster metal paint can save a original tapped type control. The oldtimer Radio techs used to take the controls apart and use pencil-lead for repairs, although it most probably didnt last very long for reliability. In my previous experiences, if WD-40 doesnt do the trick, its best to replace the control with a new one, or take two pots apart and make one good one by subbing parts. In that case, a dremmel-tool & JB Weld comes in handy. JB Weld is non-conductive and allows replacing some parts without using small brads-type rivets if necessary.

I actually ended up using WD-40 on the control and the scratch is gone. WD-40 tends to be my first tool when fixing scratchy controls on my vintage transister radios. I usually get out the Deoxit only if the WD-40 doesn't do the trick.

OT: I have found the Deoxit is quite helpful with wiring connections, fuse blocks, etc on my old Volkswagens. I end up using more of it on my old cars than my old radios.