Rub of the green

You may notice your ball is covered in mud or marked up when you get to the green. By all means, feel free to clean it. Just do it on a towel and not the green, for a competitor can accuse you of "testing the surface" which results in a penalty. This rule is murky; "intention" of the act has to be defined.

Avoid any confrontation by wiping your ball with a towel.