I had never seen a valve assembly so bad. When I first arrived to the job, the valve box was filled with water, and I began to try to pick away the roots off the valves. I quickly realized my efforts were futile, so explained to the homeowner that it was in his best interest to replace all the valves and build a barrier in the ground to prevent roots from spreading into the new valves. So, we excavated the box, installed 3 new valves, lined the ground around the valve box with 2 layers of 6 mil plastic, put rocks over the plastic, and then set the valve box. This was a few years ago, and so far the roots have not infiltrated the valves!