Each of us used to bring 4-5 large garbage/leaf bags to every Dead show. After the show most people would clean up their area, and we used the extra bags for the jerks who did not.
There was a quote from a sheriff in Tennessee or Arkansas. The Dead had played for a few days, and the local sheriff was quite worried about all the hippies coming to town. After all the shows were done, the sheriff did a complete 180. He stated that the town was cleaner than before the Dead showed up. He invited them back any time.
I never went there.
Old: large trash bags for litter
New: large trash bags containing body parts found by police