Contrary to popular belief grooves do not put spin on the golf ball when you strike it. It is a clean face and loft that puts spin on the ball but it is the clean grooves that help make the face clean when you strike the ball. When you strike the golf ball, grass, dirt, and water are supposed to go into the grooves so that the golf ball makes as clean contact with the face of the golf club as possible. If the grooves are not clean – all of that grass, dirt, and water will be in between the golf ball and the face of the club.
To clean the grooves of a club it is best to use a tee or other special groove cleaning tool. If you keep your grooves clean the ball will spin and be more predictable from shot to shot.