Dana,, the best way is to get a small (1-2 oz) with a "needle" type dispenser. It will either come filled with lightweight oil, or you can fill it yourself. Lay the tip of the dispenser on the axle where it enters the bushing (either side) and let a SMALL amount of oil trickle out. Rotate the wheels and you are done. See the link below.
http://www.slotcarcorner.com/Super-Lube ... z-p39.html