My sprinklers were all very overgrown with grass so I made a 3" hole saw to help clear out the area. You put a 1/4-20 bolt in the center and use a nut to hold it in place. It does a good job of breaking up hard dirt and grass around the sprinkler head.
To help extract the sprinklers I made hand tools that grab on to a Toro 570 and another for my Hunter PGP sprinklers.
See more and read about it on my blog post: