I agree with Chris, and Dan has a simple solution to the signage issue. Combine, both members have very good answers for resolving the trash can problem and of keeping other people from useing and leaving the trash can full.
Although, I also have two or three complete (state regulated) metal white reflective signs with "No Littering" in black reflective print, including the metal (green painted) channel post for each as well. I will donate and install them for the SWXC camp site and we could anchor them in the ground with concrete. After we find out what TMTC says about the Jeep camp site, port-a-john and all issues to be submitted in the proposal......