During league play tonight a guy on the lanes next to us takes out his liquid ball cleaner and starts cleaning his ball.  Correct me if I'm wrong, but my understanding is you can only wipe your ball off with a dry towel after competition has begun.  When we bolwed the city tournament about a month ago, the city association secretary called someone on this rule when he was cleaning his ball during the city tournament.  Does anyone know if this rule is specific only to tournaments or does it also apply to league play?  Please give the rule reference if you know the correct answer.