leave things as you would like to find them

We went to Tredegar Park and had a great time but one bloke didn't have the courtesy to rinse the wash basin after shaving. Then as the weather was so good we went to  Cirencester and had a fabulous week there but for one person who didn't pick up after his/her dog. The dog field is first class with three dog bins and shovels  provided. I don't think it is too much to ask members to leave things as you would like to find them.