 Under Law 41, subsection 3 of the Laws of Cricket, the ball may be polished without the use of an artificial substance, may be dried with a towel if it is wet, and have mud removed from it under supervision; all other actions which alter the condition of the ball are illegal.These are usually taken to include rubbing the ball on the ground, scuffing with a fingernail or other sharp object, or tampering with the seam of the ball.Generally, the purpose of altering the state of the ball is to achieve more favourable bowling conditions.