Here is the rule outlining the fact that "No foreign material may be placed on the outer surface of the ball". It is in the USBC rulebook Section 1: Bowling Ball Specifications:
Section 1. Bowling Ball Specifications
a. Approved Equipment
1. Bowling balls used in competition must be USBC approved and identifiable as a ball listed in the “Approved Bowling Balls†list located on the Specifications/ Certifications page of bowl.com.
2. For identification purposes, each ball must have some form of serial number (this may be engraved or re-engraved by the bowler), manufacturer’s name/logo and ball name. Since all bowling balls manufactured prior to the creation of the ball list (January 1991) have been previously approved, the acceptance of these balls is at the discretion of the tournament management or league official.
If my bowling ball’s serial number has been removed or is no longer visible on the ball, is it still legal/acceptable to use in USBC competition?
If the serial number can no longer be identified, it must be replaced by engraving another serial number provided the ball’s original product name and manufacturer’s name are still visible. The manufacturer’s name, product name and the serial number must be visible for the ball to be used in USBC competition. These items must be included to verify that it is an approved ball. (See USBC Equipment Specifications — Bowling Balls)
b. Surface
1. The surface of a ball must be free of all depressions or grooves of specific pattern, except for:
a) Holes or indentations used for gripping the ball
b) Identification letters and numbers,
c) Incidental chipping or marring caused by wear.
2. No foreign material may be placed on the outer surface of the ball.3. The introduction of metal or any other substance not comparable to the original material used in the manufacture of the ball is prohibited.
4. If the surface friction of the ball is altered by sanding or polishing, the entire surface of the ball must be sanded or polished in a uniform manner.
here is the actual link to that section of the rulebook, hope this helps:
http://www.bowl.com/rules/rulebook.aspx--------------------
MainePBAEdited on 12/14/2007 10:31 PM