Thanks for the tips!
I ended up yanking the switch for inspection. Turns out it was easy peasy to take apart -- waterpump pliers were used to gently pry the crimped housing away from the plastic base (with the terminals).
Very simple innards -- 3 basic parts, a plastic disk with 3 springs to keep pressure on the brass contact ring, which rubbed against specific switch post tabs on the plastic rotator base plate (the one with the screw terminals on its reverse outside).
All parts were marked to keep in their original position.
All parts were then cleaned with varsol and buffer wheel.
The small cone springs were stretched out just a touch, and the whole works was reassembled. The case was then restaked to the plastic base.
As for the screw contacts, all 3 (batt, ign, acc) were polished, and rubber grease was used for my dielectric when reconnecting the various wires, etc. As an added precaution against any shorting, some heatshrink tubing encased the terminals as well.
Verdict: sure starts better now with full voltage (6.25v) rather than the measily 4.25v that was lost through corroded contacts inside (due to tracking debris from keylock), and outside screw terminals.
Hope this description helps any others who might need to rebuild their ignition switch.
