Couple of Notes on and around the green.
One is not allowed to repair anything on one's line when off the green EXCEPT for ball marks and hole plugs that are on your green. A divot hole or unrepaired ball mark on the fringe or near the green should be left as is until you have completed the hole. Then go back and replace the divot or flatten the pitch mark.
An exception is made for repairs made which are very unlikely to affect play. For example, you are 100 yards away and waiting for the green to clear. I
" Nevertheless, you'll occasionally come across spike marks on the green and be tempted to press them down. DON'T: That act constitutes a two-stroke penalty."
You can remove loose impediments. Things such as sand, soil, stones, twigs, insects, and goose droppings. You can remove these things any way you want, provided you don't press anything down into the turf or test the surface.
You can repair those little craters created when a ball hits the green.
You can repair old hole plugs created when the superintendent's staff move the cup from location to another.
You can place your putter down in front of your ball when you address it (remember, don't press down).
You can touch the line in the process of measuring, lifting or replacing your ball or to remove a moveable
obstruction such as a coin left on the green by the group in front of you.
Once you putt out, provided you aren't aiding a fellow competitor with his or her putt, you can tap down spike marks, fix a damaged hole (sometimes a part of the circumference caves in) or push the hole liner back down (they sometimes get pulled up when the flagstick is removed.