Rules of Golf
The USGA, in conjunction with The R&A in St. Andrews, Scotland, writes, interprets and maintains the Rules of Golf to guard the tradition and integrity of the game.The two organizations are joint authors and owners of The Rules of Golf and Decisions on the Rules of Golf.Through an agreement with The R&A, the Rules jurisdiction of the USGA includes only the United States, its possessions and Mexico.The latest version went into effect Jan. 1, 2012, with the next revision taking effect Jan. 1, 2016.
Golf Rule 21 - Cleaning Ball
CLEANING BALL: The key to this rule is knowing when you can lift your ball. The most common place a ball is cleaned without penalty is on the green. The places where a ball may be lifted but not cleaned include: (i) when a ball is lifted to determine if it's unfit for play, (ii) to identify, (iii) when lifted due to interference or assistance.
PENALTY: one stroke and the ball must be replaced.
TIPS: (i) a ball may be cleaned anytime its lifted except in the three above instances. Be extremely careful when on the fringe of a green. I've seen players lifting their ball for interference and tossing it to their caddy to clean. (ii) mark your ball before lifting if it's to be replaced. (iii) if you start to clean the ball when not permitted, and realize you just incurred a one stroke penalty, you might as well finish your cleaning job.