Simpler Rules: Rule 23

Rule 23: Loose Impediments 

A loose impediment may be removed at any time, without penalty. However, if the ball lies anywhere on the course other than on the putting green and the removal of a loose impediment by the player causes the ball to move, Rule 18-2a applies. 

On the putting green, if the ball or ball-marker is accidentally moved in the process of the player removing a loose impediment, the ball or ball-marker must be replaced. There is no penalty provided the movement of the ball or ball-marker is directly attributable to the removal of the loose impediment. Otherwise, if the player causes the ball to move, he incurs a penalty of one stroke under Rule 18-2a. 

When a ball is in motion, a loose impediment that might influence the movement of the ball must not be removed. 

PENALTY FOR BREACH OF RULE:

Match play – Loss of hole; Stroke play – Two strokes. 

(Touching line of putt – see Rule 16-1a)