(3) Deliberately Changing Club’s Playing Characteristics During Round. A player must not make a stroke with a club when they have deliberately changed that club's characteristics during the round (including while play is stopped under Rule 5.7a):
By using an adjustable feature or physically changing the club (except when allowed to repair damage under Rule 4.1a(2)), or
By applying any substance to the clubhead (other than in cleaning it) to affect how it performs in making a stroke
Exception – Adjustable Club Restored to Original Position or Non-Permissible External Attachment Removed: There is no penalty and the club may be used to make a stroke in the following two situations:
If a club’s playing characteristics were changed by using an adjustable feature and, before the club is used to make a stroke, the club is restored as nearly as possible to its original position by adjusting the feature back to where it was.
A non-permissible external attachment (such as a sticker on the club face) is removed from the club before the club is used to make a stroke
Penalty for Making Stroke in Breach of Rule 4.1a: Disqualification.