For serious cleaning, I use Zippo lighter fluid and 0000 steel wool (mask off the pickups first to protect them from metal dust from the steel wool). For re-oiling I'm using Gerlitz guitar honey, or whatever it's called (don't have it out right now). However, for years and years I have used clarinet bore oil. Available at most band instrument shops, and not very expensive at all compared to the "specially formulated for fretboard" stuff. The only reason I have the Gerlitz stuff now instead of bore oil is that I was already at Guitar Center and didn't want to make a special trip for a $2 bottle of fluid.