irishrose,
I've not yet seen a clone that uses grease in the motor. If yours is oilable it will have a small oil hole above where the armature shaft bushings would be on the ends of the motors. Some do not have oil holes.
When I've taken motors apart for rewiring that don't have oil holes, I soaked the bushings and if equipped the felt around the bushings in oil. Removed the excess and put 'em back together.
Otherwise I'm not sure how to go about oiling motors without oil holes.
Joe