They are probably something called Comm Drops. Trick used in slot car racing. I do NOT recommend doing it though. It can lower the lifespan of the motor.
Just get some basic 3n1 oil and some electric motor cleaner. Clean the motor with the cleaner then put one tiny drop in the gear end and an even smaller drop in the bell/plastic end.
If you still want to use Comm Drops check out
http://rcvehicles.about.com/library/...101_cdrops.htm for info on making your own.
BTW: Comm Drops may not be allowed in competition.