A couple of years ago the farmer at our club site lost a prize bull after he'd eaten some poisonous ragwort, others became ill.
He asked us if we'd go down one Sunday and go around all his fields pulling out the ragwort, a bunch of us went down to do it, the farmer supplied the landrovers and pick up trucks for us to use,
we had a good enjoyable day doing it and were rewarded with some new fields to search later where some of us had some nice finds,