Question: - In matchplay a player concedes the opponents' next stroke by knocking the ball back to him with his putter. Should the player be penalised for testing the surface of the Putting Green?
Answer: - No
Such a casual action is not a breach of the Rule
The rule book is unclear but the above statement is from the R&A's Decisions on the Rules of Golf (16-1d/1)
This is also the case if the player picks up the ball and rolls it to his opponent.
It is however always best to pick up the ball and give it to the player.
Question: - May a player clean his ball by rubbing it on the Putting Green?
Answer: - Yes
Providing the act is not for testing the surface of the Putting Green. It is recommended that the ball should be cleaned in other ways to eliminate any question as to the player's intention.
(R&A's Decisions on the Rules of Golf 16-1d/5)