It depends. If you know the people there (as randyjawa apparently does), they will let you in. I've done that exactly once. I got a 1973 Schwinn Varsity, which I still ride, from the city dump. I was dropping off something else and spotted the bike. I asked the guy there if I could take it and he replied, "You're not supposed to take stuff from the dump, but since you asked..... go ahead."