5-2. Foreign Material
Foreign material must not be applied to a ball for the purpose
of changing its playing characteristics.

5-3. Ball Unfit for Play
A ball is unfit for play if it is visibly cut, cracked or out of
shape. A ball is not unfit for play solely because mud or other
materials adhere to it, its surface is scratched or scraped or its
paint is damaged or discoloured.
If a player has reason to believe his ball has become unfit for
play during play of the hole being played, he may lift the ball
without penalty to determine whether it is unfit.
Before lifting the ball, the player must announce his intention
to his opponent in match play or his marker or a fellowcompetitor
in stroke play and mark the position of the ball.
He may then lift and examine it provided that he gives his
opponent, marker or fellow-competitor an opportunity to
examine the ball and observe the lifting and replacement. The
ball must not be cleaned when lifted under Rule 5-3. If the
player fails to comply with all or any part of this procedure, he
incurs a penalty of one stroke.
If it is determined that the ball has become unfit for play
during play of the hole being played, the player may substitute
another ball, placing it on the spot where the original ball lay.
Otherwise, the original ball must be replaced. If a player
substitutes a ball when not permitted and he makes a stroke at
the wrongly substituted ball, he incurs the general penalty for
a breach of Rule 5-3, but there is no additional penalty under
this Rule or Rule 15-1.
If a ball breaks into pieces as a result of a stroke, the stroke is
cancelled and the player must play a ball without penalty as
nearly as possible at the spot from which the original ball was
played (see Rule 20-5).

Note: If the opponent, marker or fellow-competitor wishes to
dispute a claim of unfitness, he must do so before the player
plays another ball.
(Cleaning ball lifted from putting green or under any other
Rule – see Rule 21)