I have used lighter fluid on an old Novar lens to clean up the hardened lubricant and it seems to have worked fine. Be sure you are in a well ventilated area. As for screwdrivers, I bought a small set of slot/phillips drivers from Radxx Shxxk and just filled a couple of the small ones down for the sizes I needed. (Robert, you could also try Cdn. Tire for the screwdriver set).
You may need to soak the lens for a while.